Effects of shoot water potential (Psi) and leaf-to-atmosphere vapor pressure difference (VPD) on gas exchange of jack pine (Pinus banksiana Lamb.), black spruce (Picea mariana (Mill.) B.S.P.), and aspen (Populus tremuloides Michx.) were investigated at the northern edge of the boreal forest in Manitoba, Canada. Laboratory measurements on cut branches showed that net photosynthesis (A(n)) and me...

Please cite this article in press as: Ripple, W.J., (2011), doi:10.1016/j.biocon.2011.11.005 The 1995/1996 reintroduction of gray wolves (Canis lupus) into Yellowstone National Park after a 70 year absence has allowed for studies of tri-trophic cascades involving wolves, elk (Cervus elaphus), and plant species such as aspen (Populus tremuloides), cottonwoods (Populus spp.), and willows (Salix s...

Spatial interactions between trees influence forest community succession. The objective of this study was to investigate how shifts in composition and proximity tree species affect stand development over time mixed systems. At six locations across the Fishlake National Forest, Utah, USA, stands where facilitation has been documented previously, tree-ring samples were collected from aspen subalp...

In a previous research note (Coopersmith and Hall 1999) we described the objectives and initial research findings of the Siphon Creek (Fort St. John) Installation of Experimental Project (EP) 1077. A second EP1077 installation, Bear Mountain, will be the focus of the present report. The previous research note (PG-17) concentrated on the effects of overtopping aspen canopies on understorey spruc...

Snow ablation modelling at the stand scale must account for the variability in snow cover and the large variations of components of energy transfer at the forest ̄oor. Our previous work successfully predicted snow ablation in a mature jack pine stand by using a one-dimensional snow process model and models predicting radiation below forest canopies. This work represents a second test of our bas...

The photoperiod is an important environmental signal for plants, and influences a wide range of physiological processes. For woody species in northern latitudes, cessation of growth is induced by short photoperiods. In many plant species, short photoperiods stop elongational growth after a few weeks. It is known that plant daylength detection is mediated by Phytochrome A (PHYA) in the woody hyb...

Although many species of bats select roost sites in large trees that are in open areas, intraspecific variation in roost-site selection may exist. We collected data on the roosting behaviour of little brown bats in the Cypress Hills, Saskatchewan, to determine the extent of intraspecific variation in roost-site selection. In addition, we examined the thermal microclimate of the tree-roosts sele...