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Red oak (Quertusrubra L.) seedlings measuring less than 1 m in height were collected from seven sites in the Québec City region. The sites were grouped according to pedology, dendrometry, and phytosociology. The object of this study was to select morphometric characteristics that are most sensitive to global differences in growth conditions. Most of the variables studied are frequently used to assess seedling performance in greenhouse or laboratory experiments. The characteristics measured included total stem height; mean annual increment of the biomass; number, mass, and length of the roots; shoot/root dry mass ratio; specific root length. Two topologic variables were also measured: the total external pathlength and the diameter of the root system, as defined by Fitter. The topologic variables and number of roots differentiated well the various groups of sites. Among the variables chosen, it is possible to estimate the value of the ones that are most difficult to assess, from less time-consuming variables.

This paper presents a new method of plot volume estimation using a limited sample of heights. It requires measurement of all diameters in the plot and a limited number of height measurements per plot within a plot-specific diameter class predefined by the method. It also requires a diameter-based description of tree form. The method utilizes a polynomial curve to relate heights and diameters, but does not provide information on the plot height structure in the form of a traditional height–diameter curve. The approach was examined using data from north-central Ontario jack pine (Pinusbanksiana Lamb.) stands. The developed method of stand volume estimation is precise and unbiased with respect to height measurements; it reduces laborious height measurements compared with traditional methods utilizing a height–diameter curve.

Genetic variation and covariation among traits of tree size and structure were assessed in an 18-year-old Douglas-fir (Pseudotsugamenziesii var. menziesii (Mirb.) Franco) genetic test in the Coast Range of Oregon. Considerable genetic variation was found in size, biomass partitioning, and wood density, and genetic gains may be expected from selection and breeding of desirable genotypes. Estimates of heritability for partitioning traits, including harvest index, were particularly high. Foliage efficiency (stem increment per unit leaf area) was strongly correlated with harvest index and may represent an alternative measure of partitioning to the stem. Estimates of foliage efficiency where leaf area was estimated based on stem diameter or sapwood area were unrelated to foliage efficiency where leaf area was measured directly. Strong negative genetic correlations were found between harvest index and stem size, and between wood density and stem size. Achieving simultaneous genetic gain in stem size and either harvest index or wood density would be difficult.

A simple system for the estimation of stem volume is presented based on the compatible stem profile and volume equations. This system can directly predict the stem volume above breast height from measurements of stem diameter at breast height and at an another point along the upper stem, and does not require any sample data for determining a parameter of volume equation. In comparison with the prediction accuracy of existing volume equations from the literature, using data from Cryptomeriajaponica D. Don, Chamaecyparisobtsusa Endl., and Pseudotsugamenziesii (Mirb.) Franco, this system has the advantage of reducing prediction error.

Patterns of decline of mature and old-growth stands of Abiesamabilis (Dougl.) Forbes (Pacific silver fir) induced by tephra deposition from the 1980 eruption of Mount St. Helens were analyzed at the landscape level using discriminant and least squares regression analysis. From an array of environmental and biological factors, only the thickness of fine A3 tephra deposit, elevation, and the relative dominance of A. amabilis in a stand showed significant effects on decline. Stand decline, a mean value of the decline conditions of individual trees in a stand, increased with increasing amounts of A3 tephra and decreased with increasing elevation and relative dominance of A. amabilis. Elevation and relative dominance of A. amabilis were positively correlated, complicating the interpretation of each variable alone; we suspect that each individually represents conditions that influenced the vigor A. amabilis predisposing it and (or) contributing to the initial tephra-induced stress and, therefore, affecting its survival and recovery.

The relationship between fine-textured soil bands and forest productivity was studied by comparing three mixed-oak (Quercusrubra L. and Quercusalba L.) stands that had little or no fine-textured banding with three stands that had bands. The degree to which soil factors could account for differences in productivity between banded and unbanded stands was examined using two methods, one based on field observations (banding codes) and the other based on laboratory textural analysis. Because stand ages were not significantly different, overstory biomass was used as an index of productivity. Mean overstory biomass in the banded stands was 312 Mg/ha, significantly greater than 170 Mg/ha measured in the unbanded stands. Mean percent clay + silt and mean banding code also were significantly higher in banded than in unbanded stands. Linear regression analysis indicated that mean percent clay + silt accounted for 57% of the variation in overstory biomass, whereas mean banding code accounted for 40% of the variation. In the oak stands we studied, variation in productivity can be explained largely by differences in soil texture associated with fine-textured bands. We also found a positive relationship between mean banding code and mean percent clay + silt (r2 = 0.90), which suggests that the field method of quantifying banding can produce values that are highly correlated with soil texture and, by extension, forest productivity.

A single tree stem was used to study the formation and vertical distribution of juvenile and mature wood in Cryptomeriajaponica D. Don. The sample tree was collected from a 45-year-old plantation with 1.5 × 3.0 m spacing at Maio-li, Taiwan. Nine diametric wood strips were cut from the tree trunk from both the east and the west aspects, starting from 0.3 m by increments of 2.5 m to the top of the tree. The widths of juvenile and mature wood were recorded with two measures, i.e., the number of rings and the width in millimetres. The relationships between both the width of juvenile and mature wood and the height and age at each level of the tree were obtained by regression methods. The relationships between the age of the cambial initial and the period of juvenile wood formation at the various height levels were also determined. It was found that juvenile wood has a conical shape with a wide base at the bottom of the tree. There is no significant difference in the ratio of juvenile to mature wood width between the east and west aspects of the tree. The impact of both the height and age at each level of the tree on the width of juvenile wood appears to differ, and a similar observation must be made for mature wood. A high proportion of the total wood volume (64%) was found to be juvenile wood. No mature wood was observed at the top of the tree. The width of juvenile wood is highly correlated with the age of formation of cambial initials counted from the year of seed germination. The older the cambial initial, the narrower is the width of juvenile wood in terms of ring count.

The crown development of red pine (Pinusresinosa Ait.) plantations originating from different initial spacings was studied between 13 and 33 years of age. First, the effect of spacing on models used to predict crown width and crown ratio from diameter at breast height (DBH) and height was examined. Models for trees of different ages that included all the spacings were found to predict crown growth measures as well as separate models derived for each spacing. Second, the following crown relative growth measures were studied: crown width/crown length (crown shape ratio), crown surface/crown volume, and foliage biomass/crown volume. The way such measures changed over time under different initial spacings was studied; these findings were compared with changes in relative growth rate (RGR), which can be used to evaluate the effect of competitive stress. Crown shape ratio decreased with an increase in DBH in the absence of severe competition, and increased with DBH under severe competitive stress. The other two crown relative growth measures were always negatively correlated with DBH; this shows that large trees use their aerial growing space less efficiently than small trees at all stages of stand development. Only crown shape ratio changed in the same way as RGR.

The development of red pine (Pinusresinosa Ait.) stands originating under different initial spacings was examined using three measures of growth efficiency that are similar in concept to relative growth rate: diameter at breast height (DBH) increment/crown width, DBH increment/crown projection, and DBH increment/foliage biomass. These three measures of efficiency decreased with increasing DBH in the absence of severe competition and increased with increasing DBH under severe competitive stress. This indicates that small trees occupied their aerial growing space better and utilized their foliage to produce stemwood more efficiently than large trees in the absence of competition, and that the effect of competition was to reverse this trend. Absolute and relative growth rates for DBH and the three measures of growth efficiency were related very significantly to absolute (e.g., crown width) and relative (e.g., crown width/crown length) measures of crown development.

This study presents a new method for assessing the impact of environmental factors on the radial growth rate of trees. The natural logarithm of the specific volume increments (SVI) were fitted to a mixed linear model, which included fixed effects for tree age when the increment occurs, year, precipitation, and temperature both in the year of growth and in the preceding year, and the geographical locale. The model also incorporates stand and tree as random effects. By fitting trees of different ages, the model is able to separate year effects from age effects. Age and year were treated as categorical variables and hence no specific form of growth curve is assumed. The model was fitted to log SVI from 84 mature sugar maple (Acersaccharum Marsh.) trees from 42 uneven-aged stands in six regions of southern and central Ontario representing a known gradient of air pollution. After adjusting for age, precipitation, and temperature effects, the log SVI increased during the first half and declined during the second half of the 20th century in five of the six regions. This suggests that factors other than those included in the model have affected growth. Air pollution remains a likely causal agent in this observed decline.

Stand structure and crown architecture of loblolly pine (Pinustaeda L.) spacing trials in Hawaii and South Carolina were examined for attributes that would explain markedly different stockabilities (stand density per mean stand DBH), respectively, 1740 and 850 trees/ha at a quadratic mean stand DBH of 25 cm. In plots spaced at 2.4 × 2.4 m, these stockabilities produced 604 m3/ha at age 25 in Hawaii, and 297 m3/ha in South Carolina. Data collected in these stands indicate that stockability differences were associated with differences in tree size-class structure, crown length, and leaf area. Both stands were characterized by a two-tiered height structure, but the crown bases of trees in the subdominant class in Hawaii extended 1–2 m below the bases of the crowns of the dominant height class. In the South Carolina stands the crown bases of both height classes were at the same level. Green crown lengths in Hawaii were 4–7 m longer than in South Carolina, and the associated crown leaf area of 63.9 m2 was five times greater. The differences in stockability was attributed to the Hawaiian site and climate, which provide a long growing season, high solar radiation, high sun angle, favorable temperatures, and a favorable soil moisture regime and foliage nutrient status, and to a lack of significant insect and disease pests. The influence of genotype on stockability was not testable with these data.

Forest inventory data collected in 1987 from the Kenai Peninsula, Alaska, were used to explore whether or not such data can be used to evaluate dynamics of a spruce bark beetle (Dendroctonusrufipennis (Kirby)) infestation there. The utility of the inventory data as an evaluation tool is shown by performing analyses equivalent to those performed by other researchers in smaller scale studies conducted on the Kenai Peninsula and comparing results. Analyses showed that extensive forest inventory data can be used to estimate areas of infestation and to establish relations among tree diameter, recent radial growth, tree stocking, state of beetle attack, and stage of infestation. Understanding of spruce bark beetle infestation dynamics on broad, regional scales, can be achieved while also obtaining extensive forest inventory data.

Crown class, site class, and breast-height age were incorporated into Kozak's variable-exponent taper equation (A. Kozak. 1988. Can. J. For. Res. 18: 1363–1368) for three species: Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western red cedar (Thujaplicata Donn), and aspen (Populustremuloides Michx.). For lodgepole pine (Pinuscontorta Dougl.), crown ratio, breast-height age, and quadratic mean diameter were incorporated into Kozak's taper equation. The effects of adding these variables to the exponent part of the taper equation on the prediction abilities of the taper model were assessed for prediction of diameter inside bark along the stem, total tree volume, and tree merchantable height. It was found that apart from the use of crown ratio for lodgepole pine, the additional variables resulted in only marginal improvements to the published version of Kozak's taper function. Therefore, the cost of measuring these additional variables is not justifiable.

A parameter recovery procedure for the Weibull distribution function was modified to incorporate monocultures and mixtures of eastern cottonwood (Populusdeltoides Bartr.) clones planted in Mississippi and Kentucky. Components of the system included functions to predict stand-level basal area and four percentiles (0th, 25th, 50th, and 95th) of the cumulative diameter distribution. Basal area was predicted as a function of surviving number of trees, dominant height, age, planting location, and the proportion of each clone planted. Clonal proportions, which accounted for 3.6% of the variation in observed basal area, were more important than differences in planting locations, which accounted for 3.0% of the variation. Interactions between clones in mixtures were not significant (p = 0.5676), but some cases of both over- and under-compensation appeared to be developing. Percentiles of the cumulative diameter distribution were predicted as functions of quadratic mean diameter, and therefore included indirect effects of both genetic and planting site differences. Only the minimum diameter (D0) was directly affected by proportions of clones planted. Most of the monocultures and mixtures of clones had smaller minimum diameters than expected for a given value of quadratic mean diameter. The predicted quadratic mean diameter and percentiles were used to recover parameters of the Weibull distribution such that the predicted diameter distribution has the same quadratic mean diameter as obtained from the stand basal area model. The predicted distributions indicated that a common stand-level model was not sufficient for accounting for variations in diameter distributions of eastern cottonwood clones. As a result of the differences in diameter distributions, monocultures and mixtures of the Texas clones appeared to have less volume and greater stand variance than the Mississippi clones.

Estimates of individual-tree narrow-sense heritability and additive genetic coefficient of variation of seven traits of forest trees were compiled from 67 published papers. Distributions of the values for each trait were characterized and compared by calculating medians and running Kolmogorov–Smirnov and Wilcoxon signed-rank tests. Generalizations are possible about at least some of the traits examined. Heritability of wood specific gravity was almost always above 0.3 (median 0.48). Heritabilities for other traits tended to be low: medians ranged from 0.185 to 0.26, and individual values generally ranged from 0.1 to 0.4. Evidence that heritabilities of form traits tend to be higher than those of growth traits was weak. The analysis of additive genetic coefficients of variation suggested that specific gravity tends to have lower values than other traits (median 5.1%), while height and diameter (medians 8.5 and 8.6%, respectively) had lower values than straightness (median 11.65%). Individual-tree volume showed the highest levels of additive genetic coefficient of variation (median 20.3%). The levels of additive genetic variation and heritabilities suggest that reasonable levels of genetic gain can be achieved by screening relatively low numbers of trees.

Multiple sensors, and alternate statistical estimators, were tested for measuring canopy transmittance in four stands under a variety of sky conditions. On a given day, stand average transmittance estimates were insensitive to degree of synchronization of the sensors used to measure under-canopy and incoming radiation. In comparison to periodic measurement of incoming radiation with a single radiometer, the use of an additional sensor in the open does not automatically improve the estimates of stand average transmittance.

Formulae for estimating log center of gravity for logs of uniform density are presented that are based on frusta of simple solids of revolution. The center of gravity position for logs shaped as cones, paraboloids, paracones, neiloids, and logs having intermediate shapes can be estimated by using these formulae. A comparison of log volume estimates was made using the center of gravity and the center of volume locations as interlog positions for diameter measurements. The center of volume was found to be better than the center of gravity for log volume estimation. However, formulae for log center of gravity should be useful for engineering applications with logs of uniform density.

A method for determining and comparing average relative stem profiles is described. Under-bark diameters at several points along the stem and the total heights were measured on 572 sample trees of Caribbean pine (Pinuscaribaea Morelet var. hondurensis Barrett & Golfari). For each tree, the total volume and the diameters under bark at several consistent relative positions along the stem (viz. 0.10–0.50 in increments of 0.05) were interpolated. The trees were categorised into three size classes depending on volume. For each tree, a true form factor corresponding to each interpolated relative position was calculated. These form factors were regressed on volume for each size class to determine the most appropriate position along the stem for use in calculating the relative diameters. A polynomial model was fitted to each size class, using relative diameter as the dependent variable and powers of relative height as the independent variables. Differences between the three equations describing the mean relative profiles were statistically significant. Mean errors for the relative diameters are also presented to indicate the accuracy of the three equations.

Dendrometer bands are commonly used to make repeated measurements of tree circumference despite their tendency to underestimate first-year growth. Underestimates of growth are generally attributed to slack remaining in the bands after installation. To test for first-year measurement errors, 60 trees were fitted with a second dendrometer band 2 years after installation of the first band. The new bands consistently showed significantly less growth than the old bands (old-band measurements were assumed to represent true growth). Regression equations were developed to relate new-band estimates to true growth. There were no significant differences in regression intercepts for the three tree species tested, but significant differences in regression slopes were detected. Comparisons between canopy and subcanopy trees and between angiosperm species (Nyssaaquatica L. and Nyssasylvatica var. biflora (Walter) Sargent) and a gymnosperm (Taxodiumdistichumn (L.) Rich.) explained 95.7% of the variance in regression slopes for the individual species. It appears that in addition to band slack, part of the first-year error in dendrometer band data may result from species differences that are related to bark and stem characteristics.

Eighteen natural second-growth stands of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) from a wide range of stand densities and stocking levels were measured for stand leaf area index (LAI) from allometric relationships (direct LAI) and the LI-COR LAI-2000 plant canopy analyzer (indirect LAI). LAI was based on one-half total leaf area (m2) per square metre of ground surface area, normal to any slope. The LAI-2000 underestimated direct LAI by 62%. The underestimate of LAI was due to the confinement of needles within branches (74%) and nonrandom branch distribution (26%). In effect, the branches behaved like big leaves. The LAI-2000 can be used to estimate LAI across a variety of stand density and stocking levels by using a single stand clumping factor of 2.63.

The relation of metabolic heat rates to growth of coast redwood (Sequoiasempervirens (D. Don) Endl.) trees was studied as a function of time in the growing season and location within the plantation. Significant within-clone variations in growth and metabolic heat rates were found among ramets growing in different sections of the plantation. Specific metabolic heat rates of all clones began to increase in early May, peaked in mid-July, and returned to a low level by September. Metabolic heat rates of individual clones, averaged over a 5- to 6-week period, were strong predictors (R2 = 0.93) of clonal height growth during that period.

Procedures and formulae are given for modeling and sampling ovendry weight of a tree bole. The models are derived from first principles, and importance sampling ideas are used to develop methods for sampling individual trees to obtain unbiased estimates of dry weight. These methods would be particularly useful for providing sample estimates of the dry weight of a stand of trees.

Three density-stressed black spruce (Piceamariana (Mill.) B.S.P.) populations that naturally regenerated following harvesting in 1970 were selected for study within central insular Newfoundland. Employing historical tree and stand reconstruction techniques, bark, stem, branch, foliage, and total mass distributions were estimated by age-class. Regression analysis was used to assess the effect of density stress on distributional indices, and stepwise multivariate analysis of variance was used to investigate dry matter partitioning patterns. Bark and foliar mass proportions increased with increasing density stress, whereas stem and branch mass proportions declined. Among components, decreased stem proportions best expressed the effects of increasing density stress on dry matter partitioning. Asymmetry within the mass frequency distributions for bark, branch, and foliar components shifted from negative skewness at low relative densities to positive values at high relative densities. Inequality (mass concentration) within the stem mass frequency distributions remained constant, whereas inequality within the bark mass frequency distribution declined in direct proportion to increasing density stress. Inequality within both the branch and foliar mass distributions had curvilinear relationships with increasing density stress: inequality increased from low to intermediate levels of density stress, but declined thereafter. Specific leaf areas did not differ among trees of varying size, suggesting that competition for light may not have been of consequence within the sampled stands. The results are consistent with a resource depletion competitive process, implying that competition within the dense second-growth black spruce stands may have been principally for belowground resources.

Long-term growth trends of blue oak (Quercusdouglasii Hook. & Arn.) at five sites in California were quantified and interpreted with respect to annual precipitation. Mean annual basal area increment (BAI) at sites with deep soil profiles or high precipitation was twice as great as growth at other sites. In general, BAI increased sharply during approximately the first 40 years of tree growth, then increased gradually or leveled off for the next 100 years. Limited data from older trees suggest that BAI decreases gradually after this point. Growth trends are relatively homogeneous within each site, but vary among sites. Most sites have relatively high correlations with precipitation compared with coniferous species at higher elevations. Interannual variation in soil moisture availability is clearly an important factor affecting annual growth of blue oak in the Mediterranean climate of California. This is the first known dendroecological study of blue oak growth trends.

The objective of this study was to examine the effect of fertilization on the allometric relations for red pine (Pinusresinosa Ait.) and ponderosa pine (Pinusponderosa Dougl. ex Laws.) growing in contrasting climates. After 2 years of treatment, fertilization did not significantly affect the allometric relations between stem or branch mass and stem diameter for either species. For a similar-diameter tree, current foliage mass and area and new twig mass were significantly greater for fertilized than for control red pine and ponderosa pine. The significant increase in new foliage mass and area occurred in the upper and middle canopy for red pine and middle and lower canopy for ponderosa pine. For a similar-diameter tree, projected (one-sided) leaf area and total foliage mass were significantly greater for fertilized than for control red pine. However, leaf area and total foliage mass did not differ between similar-diameter fertilized and control ponderosa pine because fertilization decreased leaf longevity. The ratios of leaf area/sapwood cross-sectional area measured at breast height (1.37 m) were 0.14 and 0.11 for control plus fertilized red pine and ponderosa pine, respectively, and were greater (but not significantly) for fertilized than for control trees, while the ratios of leaf area/sapwood cross-sectional area measured at the base of live crown were significantly greater for fertilized than for control red pine and ponderosa pine.

Correlations and functional relationships of sapwood and annual ring cross-sectional areas versus the number of leaves supported inside the live crowns of red oak (Quercusrubra L.) were found, based on analyses of six 20- to 25-year-old oaks from monocultures in southern Ontario. Differences in numbers of leaves supported across intervals inside the crowns were compared, using correlation analyses, with the corresponding differences in conductive sapwood (outer two annual rings) cross-sectional areas, and the current and previous year's annual ring's cross-sectional areas. These analyses showed that the current year's annual ring area had a lower correlation with number of current leaves supported (R = 0.918, P 2 × PRA1.14 − 137.9. The close relationship between current foliage and previous annual ring area may reflect a developmental link between foliar primordia, which will become the following year's foliage, and the cross-sectional area of the supporting xylem.

The estimation of tree top-kill volumes is an important component of quantifying defoliation impact of severe budworm (Choristoneurapinus Freeman) defoliation on jack pine (Pinusbanksiana Lamb.) trees. Field survey is the only method by which this assessment is currently undertaken. This study evaluated an alternative methodology based on large-scale aerial photo (1:900) measurements and a taper model fitted for jack pine. This included generating linear models for the prediction of actual top-kill length from photo-measured top-kill length, the prediction of DBH from photo-measured tree height and crown area, and the estimation of top-kill volumes from a jack pine taper model. The set of three linear equations fitted with ordinary least squares resulted in top-kill volume estimates that showed no bias. The volume of damaged trees not visible on photographs was less than 1% of the volume of all damaged trees, and therefore adjustment for missed trees was not considered necessary. The methodology is convenient to implement, and if combined with forest sampling procedures, the projection of tree top-kill volumes to the stand level can provide an estimate of defoliation impact. The methodology is also potentially suitable for assessing other insect defoliation impacts that cause top kill.

Stem analysis of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and white fir (Abiesconcolor (Gord. & Glend.) Lindl.) advance regeneration 20 years after overstory removal showed that both species can respond in height growth to become dominant components of future stands on medium- to low-quality sites with a Mediterranean climate. Average annual height growth of both species nearly doubled on site classes III and IV during the first 5 years after release and continued to increase over the 20-year period of observation. Trees on the poorer site class V responded more slowly, but achieved similar 5-year periodic annual height growth after 20 years. Regression analyses indicated that prerelease height growth and site class were generally the most important variables in describing height growth after overstory removal, but regression equations left much variability in growth unexplained. Discriminant analysis was used to develop functions that identified trees meeting or exceeding specified levels of average annual height growth 5, 10, or 20 years after release; the classifications were generally successful at least 70% of the time.

Tree-ring data from the USDA Forest Service Forest Inventory & Analysis and other independent sources were used to study coincidence of changes in growth and large-scale disturbances. Numerous studies report that mean radial growth of red spruce (Picearubens Sarg.) declined synchronously throughout its range in the early 1960s. We use red spruce tree-ring data from most of the major studies to show that the synchronicity of red spruce growth decline is likely the outcome of the large-scale disturbances that occurred throughout the northeastern red spruce ecosystem in the late 1930s to early 1950s. Large-scale disturbances are either not detectable or not present in the same time interval in the southern Appalachians. This appears to correspond to an absence of a 1960s radial growth reduction in this region.

To assess temporal dynamics of ectomycorrhizae (ECM) on red pine (Pinusresinosa Ait.) seedlings, numbers of ECM per gram of dry root were compared with temporal changes in seedling height, basal diameter, above- and below-ground (coarse root) biomass, shootroot ratio, and leaf water potentials. Bare-root red pine seedlings (3-0 stock) planted on three sites in upper Michigan in June of 1984 were destructively sampled on a monthly basis (May–October) from 1985 to 1989. Three morphological types (brown, black, and white) of ECM were observed and counted. Average numbers of total and brown-type ECM per gram of dry root increased rapidly during the 1985 growing season, decreased from August 1985 to 1988, and appeared to increase slightly in 1989. Shoot weight, root weight, total height, basal diameter, and shoot:root ratio of red pine seedlings steadily increased. Temporal changes in numbers of total and brown-type ECM were significantly correlated with all seedling characteristics (p

Longleaf pine (Pinuspalustris Mill.) tree-ring data were obtained from an old-growth stand located in Thomas County, Georgia. The tree-ring chronology from the pine stand is composed of a collection of cores extracted from 26 trees ranging in age from approximately 100 to 400 years. These cores were prepared, dated, and measured, and the resulting data were examined with dendrochronological and statistical techniques. Beginning in approximately 1950 and continuing to the present, annual increments of all age classes examined in this study have increased, resulting in an average annual ring increment approximately 40% greater in 1987 than in 1950. When compared with expected annual increment, the increase for 100- to 150-year-old trees is approximately 45%, while the increase for 200- to 400-year-old trees is approximately 35%. In terms of stand-level aboveground biomass accumulation, the increased growth has resulted in approximately 5% more biomass than expected. The increased growth cannot be explained by disturbance; stand history; or trends in precipitation, temperature, or Palmer drought severity index over the last 57 years. Increased atmospheric CO2 is a possible explanation for initiation of the observed trend, while SOx and NOx may be augmenting continuation of this phenomenon.

The Kalman filter procedure was used to evaluate temporal variation in associations between physiologically based climate indices and radial growth of black oak (Quercusvelutina Lam.) and white oak (Quercusalba L.) at seven similar sites along the Ohio River corridor acidic-deposition gradient. Physiological response variables were derived by a model that used daily weather data to estimate effects of climate on growing season net photosynthesis and woody respiration. Correlations between oak radial growth indices and physiological response variables deteriorated over the period of record (1900–1987) at all seven study sites; there was no spatial association between the deterioration and the acidic-deposition gradient. This deterioration of growth–climate correlations was temporally associated with decreased growing season temperature at all seven sites; no consistent temporal trend was found for growing season precipitation. The effects of decreasing temperature on modeled physiological response variables included increased net photosynthesis and decreased woody respiration. These results suggest that recent assessments of relationships between acidic deposition and forest condition in the Ohio River region have been done during a time period of relaxed climatic stress and may have underestimated pollution–climate stress interactions.

Aboveground biomass and aboveground net primary production (ANPP) were determined for leaf, branch, and bole compartments of cove forests in the Great Smoky Mountains, Tennessee. The sample plots included young stands (42-63 years following agricultural abandonment) and old stands with no history of logging or catastrophic fire. Tree species, diameter at breast height (DBH), and 10-year radial growth increment data were collected on plots of 0.4–1.0 ha. Biomass was estimated with species-specific allometric equations for the Great Smoky Mountains and eastern Tennessee. ANPP was estimated using diameter growth measurements to determine biomass accumulation over the preceding 10-year interval. Biomass estimates for the predominantly deciduous old-growth stands ranged from 326 to 394 Mg•ha−1 on plots ≥ 0.4 ha. These were consistently greater than the corresponding estimates of 216–277 Mg•ha−1 for young stands. The old Tsuga-dominated stands had the highest biomass estimates of 415–471 Mg•ha−1 for 1.0-ha plots. Annual ANPP estimates were high (11.7–13.1 Mg•ha−1) among the young stands. These stands had particularly high bolewood production. ANPP of the old-growth plots ≥ 0.4 ha ranged from 6.3 to 8.6 Mg•ha−1•year−1 for the deciduous stands and 8.0–10.1 Mg•ha−1•year−1 for the coniferous–deciduous stands. Previous biomass estimates for primeval cove forests were well above temperate forest means of 300–350 Mg•ha−1. Our estimates based on larger plots were lower than previous estimates of 500–610 Mg•ha−1, but they still exceeded temperate forest means. Our deciduous values were 26–94 Mg•ha−1 above the temperate deciduous forest mean of 300 Mg•ha−1, and our Tsuga–deciduous values were 65–121 Mg•ha−1 above the temperate coniferous forest mean of 350 Mg•ha−1.

Nine multipurpose tree species (Acaciacatechu (L.f.) Willd., Acacianilotica (L.) Delile, Albizialebbeck (L.) Benth., Azadirachtaindica A. Juss., Dalbergiasissoo Roxb., Meliaazedarach L., Morusalba L., Prosopiscineraria (L.) Druce, and Ziziphusmauritiana Lam.) growing in the dry monsoonic climate of northwestern India showed a wide variation in growth pattern and shoot architecture. Six-year-old trees growing in plantation monocultures were sampled. The growing period varied from 194 days in D. sissoo to 301 days in A. nilotica. Annual shoot extension and radial growth varied from 20.6 to 111.2 cm and from 2.2 to 9.3 mm, respectively. Significant differences were found (P

A system of three conditioned equations is used to describe whole-tree taper for western hemlock (Tsugaheterophylla (Raf.) Sarg.). Geometric attributes of the system are predicted as empirical functions of DBH and total height. This allows for a wide range of predicted stem profiles without risk of illogical profile predictions for any tree size. Fitting is by multivariate nonlinear regression, where the dependent variables are inside-bark diameters at 12 points on each sample tree. Residual analysis shows that the system does mimic the data in the prediction of different profiles for various combinations of DBH and height. The resultant system can produce analytically tractable estimates of volume. The goodness of fit of the compatible volume estimator is comparable with that of the best whole-tree volume equations. A product of the analysis is a multivariate description of the error distribution; this could have application in the development of profile prediction systems that utilize diameter measurements at multiple heights.

A site productivity measure based on the relationship between total tree height and diameter at breast height of dominant and codominant trees was presented for four major tree species (white spruce (Piceaglauca (Moench) Voss), lodgepole pine (Pinuscontorta Dougl.), trembling aspen (Populustremuloides Michx.), and black spruce (Piceamariana (Mill.) B.S.P.)) growing in boreal mixed-species stands in Alberta. The measure is based on a three-parameter modified Weibull function fitted to growth data from permanent sample plots using the difference-equation method; R2-values ranged from 0.90 to 0.97. The measure has many logical properties similar to those of the site-index approach and produces curves that are polymorphic and reference-diameter invariant. It can be used as a simple and quick method of quantifying site productivity for uneven-aged and (or) mixed-species stands.

A general method of extending stem-profile prediction systems is developed. Deviations about a two-point system (based on DBH and total height) are described by the multivariate normal distribution. Once the distribution is characterized, it can be conditioned on any number of upper stem measurements using easily applied statistical relationships. The result is a smooth profile prediction that passes through all measurement points. Volume estimates are obtained by numerical integration. An analysis of a three-point application shows significant reductions in variance for most of the stem length. The variances of volume estimates are correspondingly reduced by factors of 2 to 10, depending on tree size.

Seasonal stable-carbon isotope patterns were measured on cellulose of tree rings from white pine (Pinusstrobus L.) and silver maple (Acersaccharinum L.) for the years 1985–1989 from open-canopy and closed-canopy forest stands in southeastern Wisconsin. The absolute δ13C values differ between species (maple more 13C depleted) and between microenvironments (closed canopy more 13C depleted). However, the seasonal δ13C patterns are quite similar between species and between microenvironments and seem to be responding to soil moisture conditions. The δ13C patterns for 1985 and 1987 have maxima prior to the end of the growing season, corresponding approximately to midseason moisture stress (increased drought severity). The severe 1988 drought was characterized by increasing δ13C throughout the entire growing season, consistent with the continuous downward trend in drought indices. These results suggest good isotope-signal reproducibility among trees and are therefore encouraging to ecophysiological studies with living trees to assess water-use efficiency and to paleoclimatic reconstructions with ancient wood.

Although Muir Grove and Castle Creek Grove are similar in area, elevation, and number of giant sequoias, various spatial pattern analysis techniques showed that they had dissimilar spatial patterns for similar-sized trees. Two-dimensional and transect two-term local quadrat variance techniques detected general trends in the spatial patterns of different-sized trees, detected multiple-scale patterns within individual size classes, and provided information on the scale and intensity of patches of individual size classes of trees in Muir and Castle Creek groves. In Muir Grove, midsized sequoias (1.5 to 2.4 m DBH classes) had major pattern scales 350–450 m in diameter, whereas the same-sized trees in Castle Creek Grove had pattern scales >1000 m in diameter. Many size classes of trees had minor patches superimposed on larger scale patterns in both groves. There may be different recruitment patterns in core (i.e., central) areas compared with peripheral areas of sequoia groves; core areas of both groves had more small live sequoias and dead sequoias than peripheral areas of the groves. Higher densities of sequoias and, perhaps, more rapid turnover of individuals in core areas may indicate (i) differences in disturbance histories and favorability of microsites in the core and peripheral areas of groves; (ii) different responses to disturbance due to shifts in the species composition of the stand and thus, the relative influences of intra- to inter-specific competition; or (iii) slower growth or lower survivorship rates in marginal habitat (i.e., peripheral areas).

The estimation of tree percent decay is important for estimating the quantity and quality of wood available for timber products. Several different independent variables have been used to estimate the percent decay of standing trees, but often the resulting percent decay predictions are poor. Other independent variables are required for more precise prediction of percent decay. The objective of this study was to examine the use of percent decay area measured at breast or stump height as a possible variable for estimating tree percent decay. Data used in testing included one species group, true fir (Abies spp.), and two species, western red cedar (Thujaplicata Donn) and trembling aspen (Populustremuloides Michx.), from several zones of the province of British Columbia. The use of percent decay area at either breast or stump height resulted in substantial improvements in the estimation of percent decay for all species in all zones. As an alternative to the expensive task of measuring percent decay area on all trees, a sampling design is suggested and one possible design is illustrated.

Spectral analysis was applied to high-elevation (≥1800 m) old-growth (≥200 years) red spruce (Picearubens Sarg.) tree-ring data from eight plots on Clingmans Dome, North Carolina. Low-frequency sine and cosine functions with wavelengths greater than or equal to 10 years accounted for between 76 and 90% of the variation in mean ring widths for all eight sites analyzed. Mean radial growth has increased and decreased no less than nine times over the last 200 years, with no evidence of constant radial growth for extended periods of time. Since the mid-1960s, radial growth has decreased and increased twice and is currently increasing through 1986, the last year of sampling. Growth in 1976 was equal to or greater than pre-1965 levels. A local maximum (mid-1960s) of the periodic cycles in radial growth coincides with the reported downturn in radial growth of red spruce at other locations in the southern Appalachians. Verification of historical growth periodicities can best be evaluated through continual monitoring of trees from a greater number of sites.

The ratio between projected leaf area (LA) and cross-sectional sapwood area (SA) of dominant and codominant balsam fir trees (Abiesbalsamea (L.) Mill.) was determined in 24 forest stands across the province of Quebec. Various physical factors proposed in the Whitehead hydraulic model, and some of the easily measured surrogates of these factors, were tested for their influence on LA:SA ratios. Average growing season vapor pressure deficit, temperature, precipitation, and stand drainage class did not significantly influence LA:SA ratios. On the other hand, LA:SA ratios were positively influenced by sapwood permeability (k), tree height, and crown length. As suggested by the model, there was a positive correlation between sapwood permeability and LA:SA ratio and a negative correlation between tree height or crown length and LA/(SA k). Increases in sapwood permeability with tree age were associated with longer tracheids having larger lumen diameters. Of the various empirical factors tested, only site quality, 5-year basal area growth, and age had a significant influence on LA:SA ratios. Sapwood cross-sectional area at breast height by itself was a reasonable linear predictor of LA for all stands (LA = −0.158 + 0.709 SABH, R2 = 0.75). Using the variables that were previously determined to influence LA:SA ratios, stepwise regressions revealed that only crown length and 5-year basal area growth significantly improved linear predictions of LA based on sapwood area. However, the increase in R2 was relatively modest, i.e., 0.83 for all three independent variables versus 0.75 for SA alone. The results from this study will be useful in integrating physiologically based measurements, such as growth efficiency, into standard forest inventory practices for balsam fir and thus could be beneficial in developing new silvicultural strategies for protecting Quebec's forest resource.

Models of compatible volume and basal area growth and yield covering a period of 10 to 45 years after harvesting were developed for second growth boreal stands of balsam fir (Abiesbalsamea (L.) Mill.). The 131 permanent plots used for the study were located near Matane, in the Gaspé Peninsula, and are part of the balsam fir–white birch ecoclimatic domain. These stands were harvested in 1934, 1944, and 1953, using a manual cut-and-bunch harvesting method that protected advance growth, and measures were taken in 1954, 1964, and 1978. The stands were moderately affected by spruce budworm outbreaks between 1950–1957 and 1975–1978. Years elapsed since release rather than total age was used as the temporal variable. Even though the characteristics of the coniferous natural regeneration were quite variable, total basal area explained an important part of growth variations of young fir stands by integrating both density and dimensions of the regeneration. Results show, within the limits of the observed densities (

This study combined an ecophysiological model and dendroecological analyses to evaluate potential effects of global warming on the physiology, growth, and mortality of white oak (Quercusalba L.) and black oak (Quercusvelutina Lam.) in the Ohio River region. The model integrated data for ecophysiology of oak species, site attributes, and daily temperature and precipitation to model nonlinear responses of stomatal conductance (gs), net photosynthesis (Pnet), and woody respiration (Rw) to variations in temperature and soil water content. Relationships between modeled physiological response indices and actual white and black oak annual radial growth indices were evaluated by regression analyses, using growth and weather data for the period 1900–1987 for seven upland oak–hickory forests. Modeled physiological response indices explained 40–60% of variation in radial growth indices. To evaluate the effects of global warming, daily temperature values for the period 1900–1987 were increased by 2 or 5 °C, without changing precipitation values, and physiological response indices were computed. Model indices generated in warming simulations were entered into dendroclimatic regression models calibrated under conditions without any warming to predict radial growth under warming scenarios. Under the warming scenarios, OAKWBAL predicted a substantial increase in growing season Rw, but little change in growing season Pnet. Warming merely shifted the period of near-maximal Pnet earlier in the growing season, without changing its duration. However, this result was somewhat dependent upon the ability of leaf-out phenology to track changes in temperature regime. The net effect of increased Rw, with little change in Pnet, was a reduction in radial growth and a higher frequency of years with climatic conditions stressful to oaks on upland sites. A historical association between severe drought and increased incidence of oak growth decline and mortality indicated that global warming could increase the incidence of decline and mortality in oak populations on upland sites similar to those in this study.

Red maple (Acerrubrum L.) is often the most abundant later successional tree species recruiting in the understories of aspen and oak dominated forests on dry–mesic sites in eastern North America. Limited evidence suggests that this species is capable of recruiting to dominant canopy positions on these sites. Given the potential for increasing overstory importance of red maple in these forests, detailed population-level examinations are warranted. In this study we examined the age and height structures of red maple populations in a bigtooth aspen (Populusgrandidentata Michx.) dominated landscape in northern lower Michigan, United States. Stem analysis was used to examine relationships between establishment times, heights, and height growth rates for overstory and understory red maple from 20 replicate plots in five stands located within a 18-km2 area. Red maple was a minor overstory component in the forests of the study area. The understories of all stands were overwhelmingly dominated by red maple. The populations were composed of two clearly defined age cohorts. The first cohort contained mostly sprout-origin individuals that established concurrently with bigtooth aspen within a 10-year period, beginning 70 years prior to the time of sampling. Mean age of the sprout-origin red maple cohort was not significantly different among stands, nor did it differ from the mean age of bigtooth aspen. Mean height of the red maple sprout-origin cohort was not significantly different among stands. Within each stand, height growth rates of these individuals were highly variable. The variability was not related to differences in stem age. Recent height growth increment of the sprout-origin stems was weakly related to position of an individual in the overstory, suggesting that most red maple were competitively suppressed by taller bigtooth aspen. Some sprout-origin red maple in all stands did approach the dominant bigtooth aspen in height growth rate. These were likely stems that were never competitively suppressed. The second red maple cohort contained seedling-origin individuals that began establishing 30–35 years after stand initiation, immediately after culmination of height increment in dominant overstory bigtooth aspen and red maple. This suggests that increasing resource availability, as a result of declining overstory vigor and canopy closure, may be a factor triggering understory reinitiation in these even-aged forests. In general, heights of seedling-origin red maple were more dependent on stem age compared with sprout-origin individuals. However, height growth rates for similar-aged individuals within the seedling cohort were still highly variable. The tallest individuals generally had the greatest rates of recent height increment, and thus were at a competitive advantage within the understory environment, but these were not always the oldest stems. There was, in fact, a trend of increasing initial height growth rate over time for the fastest growing seedling-origin individuals, again suggesting that resource availability in the understory was increasing over the course of stand development. Red maple's overwhelming understory dominance and ability to reach dominant canopy positions in the stands examined suggests a potential for increasing overstory importance on dry–mesic sites. Life history attributes, including shade tolerance, vigorous resprouting potential, and the ability to respond with increased growth upon release, may foster the development and maintenance of a red maple dominated cover type in the Great Lakes region.

A parameter recovery procedure for the Weibull distribution function, based on diameter percentiles, was modified to incorporate the effects of interfering vegetation in young Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco var. menziesii) plantations. The applicability of the system was tested by using data from sites in the Coast Ranges of Oregon and Washington and in the Siskiyou Mountains of southwestern Oregon. Four percentiles (0, 25th, 50th, 95th) of the cumulative probability distribution were predicted as functions of quadratic mean diameter and age. In the Siskiyou study, cover and total vegetation control affected quadratic mean diameter and all four percentiles; intensity of the vegetation treatments affected the 0 and 25th percentiles, and the interaction between intensity and timing of treatment affected quadratic mean diameter. In the Coast Ranges study, only quadratic mean diameter was affected by cover of woody vegetation, while quadratic mean diameter and the 25th percentile were significantly affected by total vegetation control. The predicted distributions showed decreasing variance with increasing cover, particularly in the Siskiyou Mountains. In the Coast Ranges study, the coefficient of variation increased with increasing cover, indicating that the variance of stem diameters was affected by average size. On xeric sites in the Siskiyou Mountains, high diameter variability in plots with total vegetation control suggests that interspecific competition may inhibit the expression of microsite variation.

Height–diameter relationships are an important component in yield estimation, stand description, and damage appraisals. A nonlinear exponential function used extensively in the northwest United States was chosen for bald cypress (Taxodiumdistichum (L.) Rich.). Homogeneity and normality of residuals were examined, and the function as well as the mean and individual prediction confidence bands were plotted. The inclusion of stand basal area as an additional independent variable provided a better fit to the data. The paper is concluded with a section on construction and use of simple and joint confidence intervals about the mean and individual predictions from the nonlinear regression.

Twenty nonlinear height–diameter functions were fitted and evaluated for major Alberta species based on a data set consisting of 13 489 felled trees for 16 different species. All functions were fitted using weighted nonlinear least squares regression (wi = 1/DBHi) because of the problem of unequal error variance. The examination and comparison of the weighted mean squared errors, the asymptotic t-statistics for the parameters, and the plots of studentized residuals against the predicted height show that many concave and sigmoidal functions can be used to describe the height–diameter relationships. The sigmoidal functions such as the Weibull-type function, the modified logistic function, the Chapman–Richards function, and the Schnute function generally gave the most satisfactory results.

A simple conceptual model is proposed concerning how leaf area efficiency (stemwood growth per unit leaf area) changes with leaf area for trees within a stand. Greater leaf area is generally associated with (i) improved light environment due to greater height and (ii) a lower ratio of photosynthetic to nonphotosynthetic tissue. Greater height and improved light environment result in higher photosynthetic production, which should increase leaf area efficiency. A lower ratio of photosynthetic to nonphotosynthetic tissue suggests that the ratio of respiration to photosynthesis increases, which should decrease leaf area efficiency. In relatively small trees, the influence of increased height (associated with greater leaf area) should more than offset the influence of the increased respiration:photosynthesis ratio; as a result, leaf area efficiency should increase with leaf area. In large trees, further increases in leaf area are associated with minimal increases in height, and leaf area efficiency should decline as the respiration:photosynthesis ratio increases. Predictions from this conceptual model were examined with data from stands of subalpine fir (Abieslasiocarpa (Hook.) Nutt.).

A method to categorize defoliation on current year's shoots of jack pine (Pinusbanksiana Lamb.) was developed. The pattern of defoliation caused by the jack pine budworm (Choristoneurapinuspinus Free.) feeding on jack pine trees was studied in a variety of locations in Manitoba and Saskatchewan over several years. In addition to differences among locations and years, the crown level from which a sample was taken, the branch within a tree, the tree within a plot, and the plot within a study location were consistent sources of variation. In general, the upper crown was most heavily defoliated and the lower crown least so. Branches, trees, and plots are random sources of variation, and the variance components associated with each such source were analyzed to determine their contribution to the overall variance in the estimate of defoliation. The relative importance of each random source of variation varied with the percent defoliation. Variation among plots was significant at defoliation levels below 45% and peaked at 25%, indicating a patchy distribution of feeding within stands in this range of defoliation. Beyond 45% defoliation, feeding was uniformly distributed among plots within a stand. Variation in defoliation among branches and trees peaked in the 50–60% defoliation range and was negligible at the extremes. Advantage can be taken of the consistent patterns of defoliation among crown levels and knowledge of the variance components of the random sources of variation to design defoliation assessment protocols. These data were used to optimize the allocation of effort, among plots, trees, and branches, required to determine the level of defoliation in stands either with fixed level of effort or to a specified level of precision.