A useful approach to monitor tree response to climate change and environmental extremes is the recording of long-term time series of stem radial variations obtained with precision dendrometers. Here, we study the impact of environmental stress on seasonal growth dynamics and productivity of yellow birch (Betula alleghaniensis Britton) and sugar maple (Acer saccharum Marsh.) in the Great Lakes, ...

Sugar maple, Acer saccharum, decline disease is incited by multiple disturbance factors when imbalanced calcium (Ca), magnesium (Mg), and manganese (Mn) act as predisposing stressors. Our objective in this study was to determine whether factors affecting sugar maple health also affect growth as estimated by basal area increment (BAI). We used 76 northern hardwood stands in northern Pennsylvania...

Silvicultural restoration measures have been implemented in the northern hardwoods forests of southern Quebec, Canada, but their financial applicability is often hampered by the depleted state of the resource. To help identify sites most suited for the production of high quality timber, where the potential return on silvicultural investments should be the highest, this study assessed the impact...

A new neolignan glycoside, (7R,8R)-7,8-dihydro-9'-hydroxyl-3'-methoxyl- 8-hydroxymethyl-7-(4-hydroxy-3-methoxyphenyl)-1'-benzofuranpropanol 9'-O-beta-D- glucopyranoside (1) was isolated from the leaves of Acer truncatum along with (7R,8R)-7,8-dihydro-9'-hydroxyl-3'-methoxyl-8-hydroxymethyl-7-(4-O-alpha-L-rhamno- pyranosyloxy-3-methoxyphenyl)-1'-benzofuranpropanol (2), schizandriside (3), lyonir...

The depletion of forest in developing countries due to extended pastures, agricultural land, fuel wood and etc. is a serious concern. Therefore planting trees for reforestation and extended forest area is a essential assignment. Forest plantation with a basic criterion affects to understory plant diversity. This effects may make some species absent or appear. The objective of this study is to a...

The northeastern United States is a predominately-forested region that, like most of the eastern U.S., has undergone a 400-year history of intense logging, land clearance for agriculture, and natural reforestation. This setting affords the opportunity to address a major ecological question: How similar are today's forests to those existing prior to European colonization? Working throughout a ni...

A set of Maple V R.3/4 computer algebra routines for the analytical solving of 1 order ODEs, using Lie group symmetry methods, is presented. The set of commands includes a 1 order ODEsolver and routines for, among other things: the explicit determination of the coefficients of the infinitesimal symmetry generator; the construction of the most general invariant 1 order ODE under given symmetries...

It is given an algorithm to obtain generalized power asymptotic expansions of the solutions of the Einstein equations arising for several homogeneous cosmological models. This allows to investigate their behavior near the initial singularity or for large times. An implementation of this algorithm in the CAS system Maple V Release 4 is described and detailed calculations for three equations are ...