Impact of Slash Burning on Nutrients in Industrial Plantations: A Conceptual Model for the Tsitsikamma, South Africa.

SYNOPSIS Slash treatment experiments were conducted after clearfelling of Pinus pinaster in the Tsitsikamma Forest Region, South Africa, to determine the effect of burning on pH, N and P budgets. pH(H2O) increased from an average of 4,49 to 4,78 and P-budgets in the topsoil increased by 60 % at the expense of a P-budget loss of 25 % in partly-consumed H (humus) layers, and a total loss of P in L and F-layers, which was completety consumed by the fire. N concentrations in the topsoil after burning ranged from 607 to 2 129 mg/kg. A volatilisation of 60 % of total N in forest floor layers, and 10 to 15 % of the total N-budget, is predicted. The increase in P and decrease in N budgets will act favourably to reduce high NP ratios, which will reduce the occurrence of Pinus radiata growth disorders experienced. The increase in P levels as a result of burning is inadequate for normal tree growth requirements, and fertiliser applications will still be needed to address the critical P shortages in the Tsitsikamma.

[1]  C. D. Ronde.  The impacts of management on nutrient cycling in plantation forestry in the southern Cape , 1992 .

[2]  D. Flinn,et al.  Harvesting effects on phosphorus availability in a mixed eucalypt ecosystem in southeastern Australia , 1990 .

[3]  W. Dyck,et al.  Nutritional consequences of intensive forest harvesting on site productivity , 1990 .

[4]  A. Macadam.  Effects of broadcast slash burning on fuels and soil chemical properties in the sub-boreal spruce zone of central British Columbia , 1987 .

[5]  K. Rosén,et al.  Increased nitrogen leaching under piles of slash— a consequence of modern forest harvesting techniques , 1987 .

[6]  W. H. Mckee,et al.  Long-term prescribed burning increases nutrient uptake and growth of loblolly pine seedlings , 1986 .

[7]  J. Ellis,et al.  IMMEDIATE EFFECTS OF PRESCRIBED BURNING ON MINERAL SOIL NITROGEN IN PONDEROSA PINE OF NEW MEXICO , 1986 .

[8]  D. Binkley,et al.  Prescribed burning increased nitrogen availability in a mature loblolly pine stand , 1986 .

[9]  M. Phillips,et al.  Extractable Soil Nitrogen Following Clear‐cutting and Burning in a Beech Forest , 1985 .

[10]  J. Simpson,et al.  Effects of low intensity prescribed fire on the growth and nutrition of a slash pine plantation , 1985 .

[11]  C. D. Ronde.  Litter Accumulation Problems Identified in P. Pinaster Stands of the Cape Province , 1984 .

[12]  P. Rundel.  Impact of Fire on Nutrient Cycles in Mediterranean-Type Ecosystems with Reference to Chaparral , 1983 .

[13]  L. Trabaud.  The Effects of Different Fire Regimes on Soil Nutrient Levels in Quercus coccifera Garrigue , 1983 .

[14]  W. H. Mckee.  Changes in soil fertility following prescribed burning on Coastal Plain pine sites , 1982 .

[15]  R. J. Raison.  A review of the role of fire in nutrient cycling in Australian native forests, and of methodology for studying the fire‐nutrient interaction* , 1980 .

[16]  C. Harwood,et al.  Atmospheric Losses of Four Plant Nutrients During a Forest Fire , 1975 .

[17]  C. G. Wells.  Effects of prescribed burning on soil chemical properties and nutrient availability , 1971 .