Competition for water and nutrients in forests

Abstract

Competition for water and nutrients between trees and other vegetation is discussed using examples from the interactions between tree and weeds in production forests, and trees and pasture in agroforestry systems. Production and economic viability of plantation forests are dependent upon sound weed management practices. Competition for water and nutrients by a plant is registered as a water deficit or a nutrient deficit. Plant responses to competition are similar to those for coping with water and nutrient deficiency in the soil. One species may have a competitive advantage over another for water and nutrients by (i) acquiring a greater proportion of available soil water and (or) nutrients, (ii) using water and nutrients more efficiently in producing biomass, and (or) (iii) allocating assimilate in ways that maximize survival and growth. The benefits from managing weeds during establishment of a stand have been demonstrated, but the value of managing understory in older stands is unclear. It is not possible to have water stress (through competition) without some degree of nutrient stress, but the opposite may not be the case in some environments. Managing competition effectively requires a clearer understanding of the dynamics of water × nutrient interactions, as well as the dynamics of the interactions between trees and associated vegetation and how this is modified by silviculture. Experiments where variables are well controlled and supported by simultaneous and regular measurements of both water and nutrients are required.

The effects of thinning intensity and tree size on the growth response to annual climate in Cedrus atlantica: a linear mixed modeling approach

“…Without additional ecophysiological measurements, the interpretation of the retained fixed effects is not straightforward because the dendrometric variables used in the LMM are proxies accounting for complex functional responses (Brooks and Mitchell 2011;Sohn et al 2013). In particular, the predicted transient growth increase induced by thinning likely accounts for an improvement of the resource availability (Nambiar and Sands 1993;Bréda et al 1995), for the enhancement of the remaining tree crown areas (Pretzsch 2014) and/or for the possible mobilization of stored non-structural carbohydrates in support of growth. The LMM provided a sound framework to disentangle management effects from the climate-driven signal and to quantify the interaction between thinning and climate on growth.…”

Response of newly planted Norway spruce seedlings to fertilization, irrigation and herbicide treatments

“…However, it has been debated whether competition for light, water, nutrients or a combination of these factors is the most limiting factor for newly planted seedlings [12]. Knowledge about the mechanism of competition between planted seedlings and field vegetation is important when modeling seedling establishment and growth, and when introducing new regeneration methods aiming at controlling the influence of competing vegetation.…”

“…Competition for nutrients has often been overlooked as an important factor for seedling establishment and growth [12]. The availability of nutrients is usually high on clearcuts as a U. Nilsson, G. Örlander result of decreased competition from removed trees, and decomposition of slash that are retained during the logging operation [4,7].…”

“…The availability of nutrients is usually high on clearcuts as a U. Nilsson, G. Örlander result of decreased competition from removed trees, and decomposition of slash that are retained during the logging operation [4,7]. However, despite the high nutrient availability, several studies have indicated that nutrients might restrict seedling establishment [1,12,16,18,19,20]. Nordborg [17] found that competition from field vegetation might restrain nitrogen uptake during the first months after planting.…”

Effect of Initial Seedling Size and Root Pruning Intensity on Above-ground and Root Development in Quercus serrata Seedlings after Transplanting

“…는데 도움을 주기 때문이다 (Burdett et al, 1984;Nambiar and Sands, 1993). 이처럼 뿌리 구조는 이식 및 조림의 성 공을 예견할 수 있는 주요한 인자이자 묘목의 품질평가에 있는 중요한 속성이지만 (Kormanik et al, 1988;Dey and Parker, 1997;Rose et al, 1997;Jacobs and Seifert, 2004), 뿌리구조의 파악에는 많은 시간이 소요될 뿐만 아 니라 때로는 부정확하기 때문에 (Bouma et al, 2000;Costa et al, 2001), 우리나라의 묘목 품질평가에 사용되고 있지 못하는 실정이다.…”