Effects Of Forest Management Practices Research Articles

Forest Type, Timber Size Class, and New England Breeding Birds

Breeding birds in pole and mature sawtimber stands of 6 forest cover types were grouped by association with timber size class, forest cover type, interactions of timber size and type, and key habitat components that occur irrespective of stand or forest type. Thirty bird species showed different distributions by forest cover type, 3 species' distributions differed by timber size class, and 13 species' distributions were functions of the interaction of cover type and size class. Breeding birds were grouped as stand obligates, forest type obligates, or species that prefer >1 forest type regardless of stand condition, prefer 1 stand condition, select a specific stand condition-forest type interaction, or are habitat generalists. The results are useful when planning the mix of types or distribution of timber size classes in the Northeast. J. WILDL. MANAGE. 51(1):212-217 Habitat selection by breeding forest birds is largely a function of habitat (Anderson and Shugart 1974, Crawford et al. 1981). The general term structure contains elements of class, stocking, and forest type. In many studies of forest bird habitat associations, stand age, plant species composition, and other within-stand features are variously used to describe forest structure. Foresters and other land managers, however, usually use the term condition to describe timber size class and stocking and composition to describe the relative proportions of tree species that the stand contains. Forest or cover type is generally understood as a categorization by dominant tree species. Knowledge of which bird species respond primarily to either class or cover type is useful to land managers because they manage size distribution or class by forest type, and, at least on public lands, need to state the effects of forest management practices on other resources, especially wildlife. This study distinguished groups of birds associated with class from those with distributions associated with cover type. We thank J. W. Lanier and J. E. McGowan of the White Mtn. Natl. For. (WMNF) for help with stand selection and facilities; L. N. Metcalf, J. J. Green, D. L. Fischer, and C. A. Carroll for help with bird censuses; J. M. Wentworth and D. D. Rudis for help with stand measurements; and D. E. Capen, S. H. Anderson, F. B. Samson, W. M. Healy, and R. G. Hooper for their thoughtful reviews. M. A. Sheremeta typed the manuscript.

Phosphomonoesterase activity in forest soils

Phosphatases are important in the mineralization of organically-bound phosphorous. Although phosphatases have been studied extensively in agricultural soils, there are few reports on phosphatase activity in forest soils, and no information on the effect of forest management practices, such as thinning and N-fertilization, on phosphomonoesterase (PME) activities. In the present study, the (PME) activity of forest soils from Shawnigan Lake and Jordan River (mg p-nitrophenol released g −1 dry soil h −1 was highest in the forest floor horizon (L-H) and decreased with depth to 60 cm in mineral soil horizons. Addition of orthophosphate and urea during the assay of PME demonstrated these chemicals competitively depressed PME activity. With Shawnigan Lake soil (L-H), the minimum rate ( V max) of PME activity was 5.71 mg p-nitrophenol released g −1 dry soil h −1. For Jordan River, V max was 3.33 mg p-nitrophenol released g −1h −1. Incubation of L-H horizon of both soils, fumigated or non-fumigated, at 30°C for up to 40 days after rewetting resulted in an initial reduction in PME activity. Comparatively, the PME activity of Jordan River soil recovered faster than that of the Shawnigan Lake soil whose activity remained very low at the end of the incubation. In field plots where trees were thinned and urea and ammonium nitrate fertilizers had been applied 2 yr previously, assays for PME demonstrated that urea fertilization and thinning depressed PME activity while ammonium nitrate did not. This study demonstrated (1) PME activity depended on soil geographic location and depth, and (2) fertilization of forests with phosphates and urea appeared to reduce PME activity and thus may have the potential to depress the mineralization of organic-P.

Soils of the cotter catchment area, A.C.T. : Distribution, chemical and physical properties

Studies on soil distribution and classification, together with their chemical and physical properties, were carried out in the Cotter Valley, a major water supply area for Canberra. Vegetative cover is mostly native eucalypt forest at high altitude and plantations of P. radiata at lower elevation; geology is diverse. Based on geologic diversity, five major soil associations were recognized, with significant differences in profile morphology, chemical and physical properties. Yellow earths occur on Silurian volcanic parent material; these soils are shallow and sandy, and calcium is the main exchangeable cation. They are moderately permeable but have low water retention. Gentler slopes on the same parent material are covered by red and yellow podzolic soils, with often dense A2 horizons. Exchangeable calcium is high in A horizons but in subsoils magnesium exceeds calcium. In the A2 and deeper horizons more than 30% of the exchangeable cations is aluminium. While red podzolics are reasonably permeable, yellow podzolics are not, and are likely to suffer surface waterlogging and are erosion prone. Profile water storage of these soils is good. Krasnozems and red earths are dominant soils on metamorphosed sediments. They are of clay loam to light clay texture and are largely base unsaturated, with aluminium the dominant exchangeable cation. These soils are permeable and have reasonable water retention, although krasnozems tend to be overdrained. The yellow podzolic soils on adamellite are coarse textured and have high bulk density. Calcium is the dominant exchangeable cation throughout the soil profile. These soils are reasonably permeable to 0.6 m depth, but water storage is low. The red and yellow earths found on granodiorite are not as dense as those on volcanic parent material, their clay content is higher, and soil profiles are deeper. About 30% of exchangeable cations is aluminium, and exchangeable potassium is rather high. These soils are moderately permeable and have reasonable water storage. All soils of the area are acid, with krasnozems and red earths being the most acid, and all have low CEC and thus low content of the metal cations. Their salt content is low, and exchangeable sodium and hydrogen are very low. The likely effects of forest management practices on these soils and on soilrelated catchment water quality aspects are discussed.

The Effect of Forest Practices on Quality of the Harvested Crop

The paper reviews the effects of forest management practices on wood quality in softwoods. The forester modifies growth in a variety of ways but most commonly by spacing, either at planting or in thinning, by pruning, and by fertiliser application. His primary objective is to enhance rates of growth but he should be aware of the consequences of his actions on wood properties. Of special importance are those properties which affect technical performance and so commercial acceptance, such as knottiness, density, grain angle and incidence of compression wood, and the extent to which these are affected by silvicultural operations forms the main part of the paper. The limited information which is available is often apparent; there is a need for further work to examine the effects of vigour of growth on most properties but especially on grain inclination and compression wood development, to distinguish response more clearly in terms of types of ring structure, age, and conditions of growth, and to seek a physiological explanation for observed changes.