The Influence of Wood Harvesting on the Nutrient Status of Two Spruce Stands

Abstract

Calculations are presented on the quantities of N, P, K, Mg and Ca in the soil and above-ground portions of two spruce-pulpwood stands on sites of average fertility in northern and southern Quebec. The magnitude of the depletions of these nutrients from the site, in full-tree and tree-length methods of logging, are compared with the available and total quantities of them in the soil. The ranges of values, from the literature, for the input of these nutrients in dust and precipitation, and the losses in leaching, are presented and discussed in relation to the logging losses.It is concluded that on both sites it is unlikely that full-tree logging will result in any reduction in growth, due to nutrient removal, during the second rotation of trees. However, nutrient depletion due to full-tree logging, particularly with respect to Ca, K and N, may require correction by means of fertilizers in forest ecosystems of marginal fertility. These are usually either dry sites with low reserves of organic matter and low exchange capacity or wet sites with excessive accumulations of organic matter. The need for further detailed studies of the nutrient cycle in different forest ecosystems is stressed.

The Fall River Long-Term Site Productivity study in coastal Washington: site characteristics, methods, and biomass and carbon and nitrogen stores before and after harvest.

“…Whole-tree harvesting removes more nutrients from the site than conventional harvesting (Boyle 1976, Egnell and Valinger 2003, Freedman et al 1981, Weetman and Webber 1972. Slash reduction and site preparation treatments such as piling and broadcast burning also affect site nutrient stores and microsite climate.…”

Clearcutting — a regeneration method in the boreal forest

“…whole-tree harvesting) as over 50% of the total N and P in most boreal species is in the foliage and branches (Kimmins et al 1985, Maliondo et al 1990. Nutrient losses associated with wholetree harvesting generally are of greater concern on poorer sites, especially in boreal forest stands of Picea mariana (Weetman and Weber 1972;Gordon 1983;Timmer et al 1983); Picea glauca, Abies balsarnea, Betula papyrifera, and Populus tremuloides on uplands (Gordon 1983); Abies balsarnea (Timmer et al 1983); and Betulapapylzjkra and Populus m uloides (Timmer et al 1983). These studies were mostly based on theoretical considerations of nutrient input and output budgets; to date there are few studies where actual tree response was measured after regeneration.…”

Alternate Strip Clearcutting in Upland Black Spruce: IV. Projected Nutrient Removals Associated with Harvesting

“…Nitrogen is the nutrient most limiting to the growth of conifers in the Canadian boreal forest (e.g., Weetman andWebber 1972, Foster andMorrison 1983). In mature boreal coniferous forests, the cycle of N from litterfall through the soil to the vegetation is commonly interrupted by N accumulation in humus (F and H horizons) (Weetman and Webber 1972), brought on in part by N immobilization in microbial biomass during the decomposition process.…”

“…In mature boreal coniferous forests, the cycle of N from litterfall through the soil to the vegetation is commonly interrupted by N accumulation in humus (F and H horizons) (Weetman and Webber 1972), brought on in part by N immobilization in microbial biomass during the decomposition process. It is difficult to generalize about the impact of N removals without examining the transformations of N in this soil in greater detail.…”

“…Personal cornrnun~cation document the large site-to-site variability in nutrient reserves, as was observed in stand nutrient contents. For example, soil Ca reserves within the effective rooting zone on acid tills varied from 44 kg ha-' (Weetman and Webber 1972) to 2324 (Timmer et a/. 1983).…”