Search

Given the large contribution of forests to terrestrial carbon storage, there is a need to resolve the environmental and physiological drivers of tree-level response to rising atmospheric CO2. This study examines how site-level soil moisture influences growth and intrinsic water-use efficiency in sugar maple (Acer saccharum Marsh.). We construct tree-ring, δ18O, and Δ13C chronologies for trees across a soil moisture gradient in Ontario, Canada, and employ a structural equation modelling approach to ascertain their climatic, ontogenetic, and environmental drivers. Our results support previous evidence for the presence of strong developmental effects in tree-ring isotopic chronologies — in the range of −4.7‰ for Δ13C and +0.8‰ for δ18O — across the tree life span. Additionally, we show that the physiological response of sugar maple to increasing atmospheric CO2 depends on site-level soil moisture variability, with trees only in relatively wet plots exhibiting temporal increases in intrinsic water-use efficiency. These results suggest that trees in wet and mesic plots have experienced temporal increases in stomatal conductance and photosynthetic capacity, whereas trees in dry plots have experienced decreases in photosynthetic capacity. This study is the first to examine sugar maple physiology using a dendroisotopic approach and broadens our understanding of carbon–water interactions in temperate forests. [ABSTRACT FROM AUTHOR]

Maple syrup, made by boiling the sap of Acer saccharum, is an important agriculture commodity in eastern Canada and New England. Although the collection season is relatively short, a rich progression in the sensory qualities of maple syrup can occur throughout the season. A risk associated with maple syrup production at the end of a season is the development of off-flavors that result in syrup with little to no commercial value. Maple syrup producers in Canada and the USA call this 'buddy syrup'. In this study, sugar maple (Acer saccharum) sap was collected in sequential samples through the harvest season from stands across Ontario. Metabolomics analysis of the sap samples was performed by high-resolution mass spectrometry. This revealed an evolution of the chemical composition, mainly occurring 30 days prior to leaf emergence. The major chemical constituent of maple syrup, sucrose, decreased sharply in late season sap, driven by microbial activity. The alditol mannitol increased in late season sap to concentrations ≥2 mg/mL and is likely an indicator of the start of photosynthesis. Amino acids, notably methionine and asparagine were present in higher amounts in late season sap. Non-targeted analysis revealed a series of related compounds that contained quaternary ammonium moieties including choline, hercynine, trigonelline, glycine betaine and carnitine increased in late season sap. These classes of compounds could act as methyl donors during the heating/evaporation of sap into syrup, affecting taste. Based on descriptions of the nature of buddy syrup and an extensive literature on flavors in foods, the amino acids methionine and asparagine were found as likely precursors to the compounds responsible for buddy syrup. [ABSTRACT FROM AUTHOR]

Mature aspen (genus Populus L..) and maple (genus Acer L.) forests appear to be high-quality breeding habitat for Yellow-bellied Sapsuckers (Sphyrapicus varius (L., 1766)). To explore some of the mechanisms that influence quality of the breeding habitat, we measured demographic and breeding resources in four forest stands each of 95-year-old quaking aspen (Populus tremuloides Michx.) and 182-year-old sugar maple (Acer saccharum Marsh.) in Algonquin Provincial Park, Ontario, from 2007 to 2009. Population density was higher, egg laying earlier, clutches larger, hatching success greater, and per capita and population fledgling production higher in maple stands compared with aspen stands. Longer nest-building and prelaying stages in aspen stands delayed egg laying by 5 days relative to maple stands. The delay in egg laying in aspen stands may have been caused by lower quality sap resources, which then resulted in lower productivity. Adults delivered smaller food loads to nests in aspen stands than in maple stands, which may have increased nestling mortality in aspen stands. Although per capita fledgling production was lower in aspen stands than in maple stands, Yellow-bellied Sapsuckers in both forests were able to replace themselves, suggesting that mature deciduous and mixed-deciduous forests, in general, are high-quality breeding habitat for this sapsucker. Les forêts matures de peupliers (le genre Populus L.) et d'érables (le genre Acer L.) semblent fournir un habitat de reproduction de haute qualité au pic maculé (Sphyrapicus varius (L., 1766)). Avec comme objectif d'explorer certains des mécanismes qui influencent la qualité de l'habitat de reproduction, nous avons mesuré les ressources démographiques et reproductives dans quatre peuplements forestiers de peupliers faux-trembles (Populus tremuloides Michx.) de 95 ans et d'érables à sucre (Acer saccharum Marsh.) de 182 ans dans le Parc provincial Algonquin, Ontario, de 2007 à 2009. La densité de population est plus élevée, la ponte plus hâtive, les couvées plus grandes, le succès de l'éclosion plus élevé et la production de petits à l'envol plus importante dans l'ensemble de la population et par individu dans les peuplements d'érables que dans ceux de peupliers. La durée plus longue des étapes de la construction du nid et d'avant la ponte dans les peuplements de peupliers retarde la ponte de 5 jours par rapport aux peuplements d'érables. Ce délai de la ponte dans les peuplements de peupliers peut être dû aux ressources de sève de moins bonne qualité, ce qui mène à une productivité réduite. Les adultes des peuplements de peupliers rapportent au nid des charges alimentaires plus petites que ceux des peuplements d'érables, ce qui peut augmenter la mortalité des petits au nid dans les peuplements de peupliers. Bien que la production de petits à l'envol par individu soit plus faible dans les peuplements de peupliers que dans ceux d'érables, les pics maculés des deux forêts sont capables d'assurer leur remplacement, ce qui laisse croire qu'en général les forêts matures décidues et mixtes-décidues représentent des habitats de reproduction de haute qualité pour ce pic. [ABSTRACT FROM AUTHOR]

The genetic model for maturity in soybean [Glycine max (L.) Merrj is a series of near-isogenic lines, but they do not span the natural variation for early maturity. The objectives of this study were to determine if a single gene in 0198-17 controls early maturity and if this is a new locus. A cross was made between 'Maple Presto' and 0T98-17, an early-maturing Maple Presto-derived backcross line. A total of 201 F3 progeny rows from this population and Maple Presto were grown at Ottawa, ON, in 1999. In 2000, F4 progeny rows were grown and 150 late-maturing and 51 early-maturing families were observed to fit a 3:1 ratio (n = 201, X² = 0.01, P = 0.90). The early-maturing allele was transferred to a 'Haro- soy' background, and isolines were grown from 2002 to 2006 at Ottawa, ON. The isolines were 9 and 6 d earlier maturing in Maple Presto and Harosoy backgrounds, respectively. To determine the independence of this locus, simple sequence repeat molecular markers were used to identify three candidate regions. The gene E8 specifically mapped to linkage group C1 between Sat_404 and Satt136. No other maturity gene has been mapped to this region. The two other candidate regions were both related to maturity quantitative trait loci on molecular linkage group L and may be inadvertently selected along with early maturity. The gene symbol E8e8 has been assigned by the Soybean Genetics Committee. E8E8 results in later maturity and e8e8 results in early maturity. The earliest Harosoy maturity isoline is now rated as maturity group 000. [ABSTRACT FROM AUTHOR]

In 2004 and 2005, the yield, leaf area, dry weight and dry weight partitions of soybeans were determined at the Agroforestry Research Site (ARS) (est. 1987, Ontario, Canada). Soybean was intercropped with poplar ( Populus deltoides x nigra DN-177 L., 556 m3crown tree−1), silver maple ( Acer saccharinum L., 308 m3), black walnut ( Juglans nigra L., 148 m3) and pecan ( Carya illinoensis Wangenh., 114 m3), or grown alone (monoculture). Yield of soybean was not different in either year between the monoculture and the black walnut or pecan intercrops. In the poplar and silver maple treatments, yield was 66 and 85% (2004 and 2005) lower than in the monoculture. Despite the fact that different tree species were used, there was a significant negative linear regression between yield and tree crown volume ( R2 = 0.76, P = 0.0049 and R2 = 0.93, P < 0.0001 in 2004 and 2005, respectively). With increasing tree crown volume, soybean tended to partition more dry matter to the photosynthetic and reproductive parts and less to structural tissue and petiole. This demonstrates the phenotypic flexibility of the crop component in agroforestry systems. Contrary to theoretical predictions, soybean leaves were thicker as shade increased (increase by 6.2 × 10−4–1.2 × 10−3 mg cm−2, per unit of crown volume), pointing to competitive interactions specific to tree-based intercrops. [ABSTRACT FROM AUTHOR]

Preindustrial forest composition for >180 000 km2 throughout central and northeastern Ontario was recreated from Ontario Crown land survey notes (1816–1955) and compared with existing forest composition derived from current Forest Resource Inventories (1998–2009) in each of Site Regions 3E, 4E, and 5E. A validation analysis was performed using the Forest Resource Inventory data to test the assumption that sampling the land survey tree species composition along township boundaries is adequate in describing the composition of the whole forest. The majority of tree species in each of the three site regions validated successfully. A binary logistic regression model allowed birch genera to be classified at the species level to aid in the interpretation of survey notes. All analyses showed significant reductions in conifers (especially red pine (Pinus resinosa Ait.), white pine (Pinus strobus L.), and eastern larch (Larix laricina (Du Roi) K. Koch)) and significant increases in maple (Acer spp.), oak (Quercus spp.), white birch (Betula papyrifera Marsh.), and poplar (Populus spp.). La composition forestière préindustrielle d’une aire de plus de 180 000 km2 dans le centre et le nord-est de l’Ontario a été reconstituée à partir de notes d’inventaire des terres publiques de l’Ontario (1816–1955) et comparée à la composition forestière actuelle déterminée à partir des inventaires des ressources forestières (1998–2009) dans chacune des régions écologiques 3E, 4E et 5E. Une analyse de validation a été effectuée avec des données de l’inventaire des ressources forestières pour tester l’hypothèse que l’échantillonnage de la composition forestière de l’inventaire des terres le long des limites de comté est adéquat pour décrire la composition de l’ensemble de la forêt. La majorité des espèces d’arbre dans chacune des trois régions écologiques ont été validés avec succès. Un modèle de régression logistique binaire a permis de classifier les bouleaux à l’espèce pour faciliter l’interprétation des notes d’inventaire. Toutes les analyses ont montré qu’il y avait une réduction significative des conifères (en particulier le pin rouge (Pinus resinosa Ait.), le pin blanc (Pinus strobus L.) et le mélèze laricin (Larix laricina (Du Roi) K. Koch)) et une augmentation significative des érables (Acer spp.), des chênes (Quercus spp.), du bouleau à papier (Betula papyrifera Marsh.) et des peupliers (Populus spp.). [ABSTRACT FROM AUTHOR]

The article discusses the waterfront revitalization initiative launched in Toronto, Ontario. The scheme is designed by landscape architect Adriaan Geuze in a joint venture with du Toit Allsopp Hillier. The waterfront will be infused with a mix of recreational and pedestrian amenities, cultural facilities and private condominiums. The design team plans to plant maple trees to re-establish the original summer greenery and autumn color spectacle of the waterfront.

We studied the short-term effects of partial cutting on the forest bird communities of mixed maple forests in an agriculture-dominated landscape in southwestern Ontario. Blocks that had been recently harvested were grouped according to provincial silvicultural guidelines (standard and heavy cuts) and compared with blocks that had been uncut for at least 24 years (old cuts). We found significant differences in forest bird community structure between standard and heavy cuts and between heavy and old cuts, but not between standard and old cuts. Heavy cuts had more species and more individuals than old cuts, the result primarily of greater numbers of early-successional species. Brown creeper (Certhia americana Bonap.) was the only species to show a significant negative response to harvesting and was the best indicator of old cuts, while indigo bunting (Passerina cyanea L.), brown-headed cowbird (Molothrus ater Bodd.), chestnut-sided warbler (Dendroica pensylvanica L.), American redstart (Setophaga ruticilla L.), and great crested flycatcher (Myiarchus crinitus L.) were all significant indicators of heavy cuts. Our research suggests that it is possible to protect native bird communities in southwestern Ontario by using the single-tree selection system to meet the minimum basal area targets and harvest intensities recommended in provincial silvicultural guidelines. [ABSTRACT FROM AUTHOR]

Partial equilibrium analysis was used to characterize the economic impact of the 1998 ice storm on the maple syrup industry in Eastern Ontario. Stochastic simulation is used to generate interval estimates of damages. We compare government expenditures on assistance programs to the estimated industry losses. Total losses to the industry in terms of changes in producers' surplus and capital losses for the baseline scenario were estimated to be $5.5 (± $0.5) million. Extensive sensitivity analysis was conducted. Losses were estimated to be $4.7 (± $0.4) million if recovery takes place faster than in the baseline scenario. Losses were estimated to be $7.1 (±$0.4) million when recovery takes longer than in the baseline case. Direct government expenditures on ice storm assistance programs to this industry were approximately $7.3 million. The relevance of this type of analysis to the development of natural disaster relief policies is discussed. [ABSTRACT FROM AUTHOR]

Research Highlights: In central Ontario, large quantities of non-industrial wood ash (NIWA) are generated and could be used as a forest soil amendment to counteract soil acidification and base cation depletion caused by decades of acid deposition. Background and Objectives: The properties and biogeochemical responses of NIWA have not been thoroughly explored, and field experiments must be conducted before NIWA can be regulated as a forest soil amendment in Ontario. Materials and Methods: In this study, soil chemistry and sugar maple (Acer saccharum, Marsh.) seedling growth and chemistry were measured in an acidic sugar bush over twelve months following a NIWA field experiment. Plots (2 m by 2 m) were established with sugar maple, white pine (Pinus strobus L.), and yellow birch (Betula alleghaniensis Britt.) NIWA treatments applied at rates of 6 Mg ha−1 along with untreated control plots. Results: Ash chemistry varied significantly among species and yellow birch ash generally had much higher metal concentrations compared with other species. Following ash application, significant increases in soil pH and calcium and magnesium concentrations were observed, however the level of response varied by treatment. Foliar concentrations of base cations in sugar maple seedlings significantly increased in ash treatments and there was no significant treatment effect on foliar metal concentrations or seedling growth. In roots and shoots, concentrations of several metals (manganese, aluminum, iron, boron, arsenic, cadmium, zinc, copper, lead, chromium, and nickel) increased after ash application, however response was most pronounced in yellow birch ash. Conclusions: These results suggest that application of NIWA can counteract the lasting effects of acid rain by increasing soil pH and base cation concentrations, as well as increasing sugar maple seedling foliar nutrient concentrations, but ashes from species with high metal contents may also increase metal availability to vegetation, at least in the short-term. [ABSTRACT FROM AUTHOR]

• The change in temperature determined the performance of introduced sugar maple. • A moderate increase in precipitation would ameliorate heat stress. • The leaf level plastic responses influence the survival and growth of sugar maple. Global climate change will lead to new combinations of temperature and precipitation patterns. Extreme precipitation events will become more common by the late 21st century due to anthropogenic warming, particularly in high latitudes; however, the specific responses of high latitude species are mostly unknown. We employed an introduction trial by transplanting temperate sugar maples (Acer saccharum Marsh) from three provenances of their native ranges within Canada, which had a mean annual temperature (MAT) ranging from 3.0 to 9.4 ℃, and mean annual precipitation (MAP) from 520 to 1190 mm. These maples were transplanted to four sites in subtropical China with a MAT of 15.8–16.2 ℃ and a MAP of 913 mm, 1001 mm, 1172 mm, 1490 mm, respectively. We measured the survival and growth of the first-year seedlings of all provenances, as well as the survival, growth, and leaf morphological and physiological traits of the seedlings of Ontario provenance after four years of acclimation. We found that the first-year survival and growth of all provenances increased with the MAP at the planting sites, peaked at 1172 mm, and then decreased at the 1490 mm MAP site, with the seedlings of Ontario provenance had the best overall survival and growth rates across all of the sites. At the end of the 4th growing season, the seedlings of the Quebec and Manitoba provenances died off, and the survival- and growth-MAP relationships of the Ontario provenance mirrored those observed in the first year. For the Ontario provenance at year 4, the major vein density, stomatal density and size, and non-structural carbohydrates (NSC) changed significantly with MAP at the introduced sites. Principal component analysis indicated that seedling survival was negatively associated with stomatal size, density and starch content and that growth was positively related to leaf major vein density and negatively to soluble sugar and NSC. Our results indicate that changes in the precipitation range determined the performance of introduced sugar maple at the introduced sites. A moderate increase in precipitation was observed to ameliorate heat stress and benefit plant growth; however, excessive water could result in a fatal effect. Moreover, our findings suggest that the plasticity of leaf morphological and physiological traits influenced the survival and growth of the introduced sugar maple under future precipitation and warming. [ABSTRACT FROM AUTHOR]