Abstract

With the decrease of forest area and increase of greenhouse gases like CO₂, it is increasingly important to estimate forest biomass and carbon storage. For a better assessment of the variation of regional forest structure and arborous layer biomass at different altitudes in Qinling forest area, we studied the environment factors and interference factors of local forest, on the 50 selective sampling plots (800 to 2300 m). The results showed that low altitude forest was more severely disturbed by human being, with its structure different from other altitudes. The arborous layer biomass was between 104.76 ± 8.97 and 40.48 ± 3.03 mg ha^-1, negatively related to altitude (r_p = - 0.456, P < 0.05), and positively related to age (r_p = 0.596, P < 0.05) and basal area (r_p= 0.667, P < 0.01). The temperature change related to altitudes and decreasing stem density were the main factors influencing forest stand biomass and productivity. The average individual biomass of broadleaved species decreased with increasing altitude, while that of coniferous species increased gradually, with some exception in low-altitude areas. The results showed that the forest biomass estimation in regional scale is different from that for larger scales. We must take into consideration inference factors and environment changes.

Key words: Arborous layer aboveground biomass, carbon pool, secondary mixed forest.