יער הקדושים – אתר למחקר אקולוגי ארוך טווח ביער נטע-אדם מחטני: ממשק עומדים בוגרים לעיצוב יער העתיד

The long-term ecological research (LTER) site in the Kedoshim Forest was established in 2009 in order to investigate key questions regarding the management of mature conifer forests in Israel and their structuring as vital, diverse resilient forests. The research is carried out in a mature Pinus halepensis forest in the Judean Mountains and examines the long-term effects of various stand thinning treatments on forest tree vitality,natural regeneration, biodiversity and ecosystem function. Twelve years following the application of treatments, the study results show that stand thinning has led to a significant increase (up to four times more) in the productivity of the trees that remained after thinning, and to a substantial reduction in tree mortality rate (up to ten times less). However, the response of the remaining trees in terms of their crown size was limited, and the leaf area index (LAI – the area of leaves per unit ground area) of the forest over story showed some inter-annual fluctuations but did not exhibit any consistent trend over the years. Following thinning,a substantial increase in the recruitment (up to five times more) and growth rate (up to two times more) of regenerating pines (Pinus halepensis) was measured. Oak (Quercus caliprinos) recruitment, on the other hand, decreased as a result of thinning and even some mortality was detected. The growth rate of established oaks in the forest under story,however, increased (up to three times more). Thinning affected plant species composition in the forest under story, and led to a significant increase in species richness (up to 60% more). The thinning treatments caused a decrease (up to 13% less) in the dry biomass production of the forest over story layer (mature pine trees) and, on the other hand,led to a gradual increase in the productivity of the understory vegetation (up to eight times more). Nevertheless, at this point, the overall LAI and productivity of the over story and under story layers together, have not yet reached the values that were recorded prior to thinning. The study findings demonstrate the long-term effectivity of stand thinning treatments for designing forest structure,controlling ecosystem dynamics and functions, andim proving forest resilience in the face of increasing water deficiency resulting from climate change