Treesearch

The objective of this study was to determine if addition of Ca, Mg, K, and P to an extremely acidic forest soil would increase early northern red oak (Quercus rubra L.) seedling growth. The O through B2 horizon of a Dekalb soil from Pennsylvania's Bald Eagle State Forest was placed in plastic cores and utilized as a growth medium for northern red oak seedlings in a greenhouse environment. After 150 days, fertilization with the selected nutrients Ca, Mg, K, and P increased greenhouse seedling height, leaf area, leaf dry weight, stem diameter, stem dry weight, and tap root diameter. Fertiliza...

Bareroot seedlings of northern red oak, white ash, yellow-poplar and white pine were planted into herbaceous communities at three forested sites in central Pennsylvania that were clearcut 0 to 1 year earlier. Seedlings were grown 4 years in the presence and absence of either an established grass or hay-scented fern community. Survival and height growth were measured annually at the end of each growing season. Fourth year results showed significant decreases in the average survival of northern red oak, white ash and yellow-poplar seedlings grown in the presence of grass or hay-scented fern....

A stochastic model of oak flower dynamics is presented that integrates a number of factors which appear to affect the oak pistillate flower development process. The factors are modeled such that the distribution of the predicted flower populations could have come from the same distribution as the observed flower populations. Factors included in the model are; the range of peak crop intervals, relative humidity in the pollination period (Wolgast 1972), number of severe storms (Cecich 1997), tree hopper (Kopp and Yonke 1973a, 1973b) and acorn weevil population (Gibson 1964), genetic factors...

Many models of landscape ecosystem development, as well as of forest stand dynamics, are based upon spatial and temporal changes in the species composition and structure of various forest strata. However, few document the interrelationships among forest strata, or the response of different strata to alterations of natural disturbance regimes. To examine how relationships among forest strata varied with stand age, we sampled a chronosequence (five age classes) of 21 second-growth (70 to 149 years old) and old-growth (≥150 years old) mixed-oak stands from a single ecosystem type within the...

Recent evidence has shown that red maple (Acer rubrum) may become a more prominent species in eastern mixed hardwood stands. This study will examine the strategies used by red maple to reach dominant and codominant canopy positions on two different stands (one mesic and one drier). Stand level data such as dbh, height, crown class, height class, and age structure will be gathered using 0.02 ha plots covering one-tenth of the area of each stand. Six plots per stand, which must contain a codominant red maple, will be randomly selected as stem analysis plots. One codominant red maple and all...

This study was conducted in a fenced 1-yr-old 70-acre mixed-oak shelterwood to determine the impact of soil scarification on species composition and the production of oak regeneration from abundant northern red oak (Quercus rubra L.) acorns. In October 1993, seven replicates were established and randomly divided into control and scarified plots. Pretreatment sampling showed that control and scarified treatments had statistically similar numbers of advance regeneration in various species categories (including total seedlings - 4,085/acre) as well as similar numbers of acorns (48,463/acre)....

Overstory competition and foraging by white-tailed deer (Odocoileus virginianus) and small mammals are cited as reasons for regeneration failure in mixed-oak stands of Pennsylvania. At Gettysburg National Military Park, deer densities are high (>0.6 deer/ha), and the mixed-oak woodlots were lacking in seedling- and sapling-sized natural oak regeneration. To promote restoration of the woodlots to Civil War condition, we examined the effects of canopy conditions and browsing by deer and small mammals on the survival and growth of planted northern red oak (Quercus rubra L.) acorns, seedlings,...

Leaf abscission and foliation responses to water stress were studied in potted plants of five Populus clones grown in a greenhouse. As predawn leaf water potential (Ψ1) fell to -3 MPa, drought-induced leaf abscission increased progressively to 30% for data pooled across clones. As predawn Ψ1 fell below -3 MPa, drought-related abscission was about 50%. When combined with abscission rates in well-watered "phenological control" plants, abscission exceeded 80-90% in the most severely water-stressed plants. Clonal variation in water stress-induced abscission was statistically significant, but...

Quantitative details about past anthropogenic fire regimes and their effects have been lacking in the central hardwood region. Here, we present fire scar chronologies from 23 oak-shortleaf pine (Quercus spp. and Pinus echinata Mill.) sites in the upper Current River watershed of the Missouri Ozarks. Dendrochronological methods were used to date 2,004 fire scars from 150 shortleaf pine sections with from 100 to more than 300 rings. Fire scar chronologies were constructed from scars dating back 200 to 400 years ago. The average mean fire-free intervals (MFI) calculated for the sites by time...

The importance of basing land management decisions upon an ecosystem perspective is becoming widely accepted. It is frequently regarded as insufficient to simply manage stands or forest cover types without considering the ecological relationships of the forest vegetation to the other components of the ecosystems, such as soils and physiography. In order to implement the policies of ecosystem management adopted by the USDA Forest Service, ecologically meaningful units of the landscape (ecosystems) must be recognized at various scales or levels. Given this justification, hierarchical...