Tree plantations

Most of the commercial tree plantations that produce wood for captive use as a raw material in manufacturing operations use a portion as fuel. Examples of short-rotation plantations are Hsted in Table 38 (127). Paper companies in the southeastern United States are reported to have short-rotation plantings also, eg, Weyerhaeuser, James River Corp., Buckeye Cellulose, and Lykes Brothers, but the intensity of maintenance is not known (127). 

The commercial use of 2,4-D has decreased substantially and (ca 1993) it has general use for home lawns to control broadleaved weeds it also is used on a limited basis to control broadleaved weeds in commercial moncotyledonous crops, eg, sugarcane. 2,4-D is used on citms when the fmit is 1/3 to 1 inch in diameter to increase fmit size and to limit fmit drop on trees more than six years old. It should not be appHed to trees that are in fliU flush. A further use includes treatment of harvested lemons at 500 mg/L to improve storage properties and to delay yeUowing (23). It is used in certain parts of the world to increase latex flow in old mbber tree plantations. 

Change of Tree Plantation Pattern over Time... 

Failures of newly established forest tree plantations or abnormal delays in tree seedling growth seldom have clear-cut causes. In the absence of knowledge of cause, foresters often attempt remedies that are unnecessarily costly or environmentally damaging, even when they succeed. Allelopathy, the direct or indirect deleterious effect of one plant upon another through the production of chemical inhibitors released into the environment, is likely a common cause of such failures or delays. 

Some production comes from wild" trees but increasingly the gum is harvested in organized gum tree plantations. 

Development of weed resistance to triazine herbicides has necessitated alternative weed control strategies. Rotation of triazines with other herbicides and combining triazines with other chemistries has been effective in ornamentals and Christmas tree plantations (Van Himme, 1989). Supplemental treatments in Christmas trees have been effective, using directed sprays of phenoxy herbicides or glyphosate before resistant weeds mature and produce seeds. Weed resistance from triazines is not a problem in most forest settings where the herbicide is applied only once or twice in a rotation, since 1 or 2 years of herbaceous weed control normally ensures survival and eventual dominance by conifers. When the conifer canopy closes, virtually all herbaceous vegetation is shaded out for some decades hence resistant weeds, if present, fail to survive from one generation to the next. 

Brown, J.H. (1980). Competition control in Christmas tree plantations. Tree Planters Notes 31(1) 16-20. 

Townsend, P. (1995b). The effect of cultural treatments on the growth and quality of a balsam fir Christmas tree plantation. Forest Research Report No. 59. Nova Scotia Department of Natural Resources, 27 pp. 

The profiling of HCHs was also similar to those of DDTs (Table 13.1). Higher proportion of both a-HCH and y-HCH were observed in various studies that indicate the use of technical HCHs and lindane (purified y-HCH) in this country. Likewise, there were differences in use of different formulations of HCH among the locations. Higher a-HCH levels in water from some locations in Java may have been due to preferential use of technical HCHs, whereas high concentration of y-HCH in several rivers and coastal areas in Sumatra Island may indicate the considerable usage of lindane. It has been reported that lindane is commonly used on palm oil tree plantations (Othman and Balasubramanian, 2001). It is plausible that this pesticide is intensively applied on palm oil tree, a common plantation crop in Sumatra Island. 

Lugo, A. E., E. Cuevas, and M. J. Sanchez. 1990. Nutrients and mass in litter and top soil of ten tropical tree plantations. Plant Soil 125 263-280. 

This chapter considers large-scale industrial tree plantations, as well as small- and medium-scale plantations for timber and land rehabilitation. Aspects that influence plantation sustainability are emphasized, and suggestions are given regarding plantation design and management. 

Finally, a key issue in nutrient management of tree plantations is to find the best compromise between ecological requirements... 

Guariguata, M. R., R.. Rheingans, and F. Montagnini, 1995. Early woody invasion under tree plantations in Costa Rica implications for forest restoration. Restoration Ecology 3 252-260. 

Lugo, A. E. 1992. Comparison of tropical tree plantations with secondary forests of similiar age. Ecological Monographs 62 1-41. 

Some of the processes that add carbon to the atmosphere or remove it, such as the combustion of fossil fuels and the estabhshment of tree plantations, are under direct human control. Others, such as the accumulation of carbon in the oceans or on land as a result of changes in global climate (i.e., feedbacks between the global carbon cycle and climate), are not under direct human control except through controlhng rates of... 

In the mid-1990s, few virgin biomass species were grown and harvested in the United States specifically for energy or conversion to biofuels, with the possible exceptions of feedstocks for fuel ethanol and a few tree plantations. This is not difficult to understand from an economic standpoint, especially if conversion costs are included. The nominal price of natural gas in the United... 

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