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Leaf tissue production was studied to determine possible successional trends. The study area was in the spruce-fir zone of the southern Rocky Mountains 15 kilometers northeast of Santa Fe, New Mexico. In this area quaking aspen (Populus tremuloides) is a successional species that is slowly replaced by Engelmann spruce (Picea engelmannii) and corkbark fir (Abies lasiocarpa var. arizonica) as succession proceeds towards the classical spruce-fir climax. Five study plots were subjectively selected to represent a successional sequence of forest stands with similar physical characteristics. The plots were arranged in a successional series by using the increase in coniferous basal area at DBH as an indicator of later stages of succession. Overstory leaf production was measured by determining the DBH of every tree greater than 2.54 cm DBH and then applying regression equations to calculate leaf biomass. Aspen leaf production was assumed to be equal to aspen leaf biomass. For spruce and fir 25% of the leaf biomass was used for leaf production. Herbaceous leaf production was collected throughout the growing season whereas shrubs were collected once at the end of the growing season. Understory leaf production decreased with succession from 71.06 g/m -year to 9.07 g/m -year. Vaccinimn scoparimn dominated four of the five plots in terms of understory leaf production (no lower than 71%), but Thermopsis pinetorum reached the highest value in the earliest successional site (33%). Shrubs contributed only a minor portion of the total leaf production with the exception of aspen which produced 82 g/m -year in one site. In this site aspen was the canopy species, but did not qualify as overstory be definition (>2 .54 cm DBH). Leaf production of aspen increased through time in the first two plots and then decreased to zero in late succession. Spruce leaf production increased from 4.86 g/m -year in early succession to 503 g/m -year in late succession. Fir leaf production was not present

Laboratory studies were conducted to determine effects of salts, metals, and their interactions on the germination and emergence of fourwing saltbush [Atriplex canescens (Pursh.) Nutt.] and alkali sacaton (Sporobolus airoides Torr.). These studies, coupled with soil evaluations, should allow one to predict and possibly alleviate germination and emergence inhibition of these two species due to excessive soil salts and metals. Fourwing saltbush germination and emergence is significantly greater with osmotic stress <-3 bars imposed by inorganic salts (NaCl, Na2SO4, MgCl2, MgSO4, or CaCl2) than by polyethylene glycol (PEG) (P <.05). Alkali sacaton germination and emergence is significantly better with osmotic stress <-3 bars imposed by NaCl, Na2SO4, or CaCl2 than by MgCl2, MgSO4, or PEG {P <.05). Data were summarized which enables prediction of percentage germination and emergence of these two species in substrates containing combinations of salts. Good germination and emergence of fourwing saltbush was observed in up to 900 ppm Zn or 150 ppm Cu, and good germination with appreciable emergence in up to 50 ppm B or 30 ppm Se. Good germination and emergence of alkali sacaton was observed in up to 75 ppm Zn, 15 ppm Cu, or 5 ppm Se, with good germination and appreciable emergence in up to 25 ppm B. Interactions of toxic concentrations of these metals combined with salts were investigated. Emergence inhibition of both species caused by 50 or 100 ppm B or 30 ppm Cu was alleviated by addition of low concentrations of salt tested. Emergence inhibition of both species with 30 ppm Se was somewhat reduced by Cl salts of Ca or Mg. The steady state diffusion gradient germination chamber developed will greatly simplify the study of the effects of various concentrations of water soluble compounds on germination. The chamber will also facilitate study of the interaction of t

Identification of dissolved organic chemicals in natural streamwaters of the Tesuque Watershed, Sangre de Cristo Mountains, New Mexico

Effects of timber stand maturity and management on some stream organic compounds

A determination of the effects of nitrogen and terpenes on spruce budworm growth and survival

Stress physiology, patterns in defensive chemistry, and spruce budworm success

Effect of recreation (trampling) on the forest floor and associated streams of aspen and conifer forests

A determination of the resistance-susceptibility characteristics of douglas-fir to the western spruce budworm

A determination of the effects of foliage quality on larval density and level of defoliation of douglas-fir trees by western spruce budworm