|
Fir (Cunninghamia lanceolata) is one of the fast-growing timber species unique to southern China, with fast growth, good material, high yield cultivation area. However, with the continuous plantations of Chinese fir plantation algebra and the area gradually increased, pure fir woodland force recession is very obvious, stand instability, the yield decreases generation. How to maintain the continued productivity of the southern forest region fir plantation ecosystem and stability has become a major issue that need to be resolved in the current forestry production, and create one of the fir and broad mixed forest is considered to be a better way to maintain long-term productivity of Chinese fir plantation . Mytilaria straight trunk, better materials, soil and water conservation, soil improvement, a fine species of of Mixed Afforestation and biological fire. In this paper, a systematic and comprehensive analysis of the 16-year-old fir plantations and fir - Mytilaria mixed forest Comparative Study from biomass, productivity, nutrient cycling, and to explore the characteristics of its mixed forest ecosystem productivity and nutrient cycling with The law, for the evaluation of mainly fir stands Sustainable Management provide a theoretical basis and practical experience. The main findings are as follows: 1. The fir - Mytilaria mixed forest with fir plantations growth quite different. Difference in the amount of two stand DBH growth performance, mixed forest slope fir DBH growth fir plantations downhill showed greater growth advantage; tree height, mixed forest fir, slope, respectively, than the fir plantations increased by 14.1%, 19.0%, 9.1%; the material Points do not rate increased by 29.3%, 26.1%, 1.9%; the stock volume 132.87 m3/hm2, the 191.83 m3/hm2, 267.48m3 / hm2, of which, sloping rate increased by 21.3%, 17.3%, mixed forest uphill slope accumulation obvious advantages compared fir plantations. Different slope positions in the same stand, the two forests growth indicators showed downhill gt; gt Zhongpo; uphill variation. 2. The fir - Mytilaria mixed fir plantations biomass varied significantly. The same slope position the fir - meter row of old mixed forest biomass ratio fir plantations; performance of two different slope positions total stand biomass: downhill gt; sloping gt; uphill. Fir - Mytilaria mixed forest uphill and the slope of each organ biomass allocation dry gt; roots gt; branches gt; leather gt; leaves, downhill performance for dry gt; roots gt; branches gt; leaves gt; leather; fir plantations of different slope positions of Biomass allocation sequence manifested as dry biomass, leaves, branches, roots, skin biomass difference is not obvious. Fir - meters laosensis the the mixed fir plantations N, P, K nutrients total accumulated difference in performance: the same slope position under the growth conditions, mixed forest, in the N accumulation downhill than Chunlin high 104.4%, 93.4%, 12.7%, P accumulation were higher than Chunlin for 53.1% of 37.7%, 59.6%, K nutrient accumulation in the uphill slope ratio Chunlin high 42.01%, 99.47%, and in the downhill Chunlin than mixed forest; same stand nutrient accumulation of different slopes were in the downhill gt; sloping gt; uphill, this variation of the two forests tree layer nutrient accumulation of differences in the same pattern. 4. By fir - Mytilaria mixed fir plantations nutrient use efficiency varied significantly. The mixed forest uphill, sloping downhill tree layer nutrient use efficiency than fir plantations high 11.5%, 9.5%, 57.0%. Different slope positions, mixed forest nutrient use efficiency presents uphill gt; downhill gt; the slope variation fir plantations performance uphill gt; sloping gt; downhill; mixed forest, downhill understory vegetation nutrient use efficiency were higher than the fir plantations, seen mixed forest stand understory vegetation can improve nutrient use efficiency. 5. The fir - Mytilaria mixed forest with fir plantations litter annual production of quite different. Same slope position stand the amount of annual litter performance for mixed forests gt; fir plantations; the annual litter were in the same stand different slope positions Downhill gt; sloping gt; uphill. Mixed forest litter size Sort: the uphill as branches gt; leaves gt; fruit gt; flowers, slope and downhill leaf gt; branches gt; fruit gt; flowers, the fir plantations showed branches gt; Ye gt; fruit gt; flowers. 6 fir - meters the old row of the mixed fir plantations nutrient retention amount, the annual return of the amount of the annual uptake and return than differences showed: the mixed forests gt; fir Chunlin. Nutrient cycling ability mixed forest slope fir plantations have a distinct advantage. Same stand the same slope positions in growth conditions, the amount of the two forests nutrient retention, the annual absorption volume performance for N gt; K gt; P; annual return in restitution than the performance of the N gt; P gt; K . Nutrient return than watching the performance of fir plantations downhill gt; uphill gt; slope, while mixed forest showed slope gt; downhill gt; uphill, indicating mixed forest slope bit Fertility conducive to the nutrient cycle. In short, compared to the fir plantations, fir meters laosensis Mixed conducive to the growth of the fir. Fir - Mytilaria mixed forest of fir tree, average DBH, volume and growing stock volume is greater than the fir plantations. And mixed forest biomass, nutrient accumulation, nutrient use efficiency, nutrient restitution than fliers presents mixed forest greater than the variation fir plantations. Visible, to create a mixed forest compared fir plantations, higher productivity and nutrient cycling also strong.
|