Pinidine is the main constituent of Pinus sabiniana and related plant species as determined, along with its chemical structure, by Tallent and co-workers over 40 years ag0.1 The complete stereochemistry of pinidine was unambiguously established by Hill to be la, usmg chemical and spectroscopic methods.2 Very recently, further work on the pinidine alkaloid contents of pine (Pinus) and spruce (Pi...

We measured sap flux in Pinus ponderosa Laws. and Pinus flexilis James trees in a high-elevation meadow in northern Arizona that has been invaded by conifers over the last 150 years. Sap flux and environmental data were collected from July 1 to September 1, 2000, and used to estimate leaf specific transpiration rate (El), canopy conductance (Gc) and whole-plant hydraulic conductance (Kh). Leaf ...

Studies of forest change in western North America often focus on increased densities of small-diameter trees rather than on changes in the large tree component. Large trees generally have lower rates of mortality than small trees and are more resilient to climate change, but these assumptions have rarely been examined in long-term studies. We combined data from 655 historical (1932–1936) and 21...

Ponderosa pine (Pinus ponderosa P. & C. Lawson) is highly suitable for management using multiaged systems. This suitability is primarily the result of a frequent, low severity disturbance regime, but also because it naturally occurs at low densities and has a long history of management to promote multiple age classes. Several different stocking control tools are available for ponderosa pine inc...

Introduction Conclusions References

The widely distributed Pinus subsection Ponderosae is a species complex that has a transition zone among taxa in the southwestern United States. In southern Arizona and New Mexico at least two recognized taxa, Pinus ponderosa var. scopulorum and Pinus arizonica or P. ponderosa var. arizonica, are known to coexist in close proximity. In this study, we report the existence of populations where th...

...........................................................................................3 PREFACE.............................................................................................4 INTRODUCTION....................................................................................4 MATERIAL AND METHODS....................................................................8 RESULTS..........