Carbon and Nutrient Pools of Coarse Woody Debris in a Natural Forest. and Plantation in Subtropical China

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1 SCIENTIA SILVAE SINICAE Vol141, No13 May, ( ; ; ) : 33 C, t hm > > > C 0178 t hm - 2, ; C 2 ( P < 0105) kg hm - 2 ;, C : ; ; ; ; ; ; :S :A : (2005) Carbon and Nutrient Pools of Coarse Woody Debris in a Natural orest : and Plantation in Subtropical China Yang Yusheng 1 Guo Jianfen 2 Lin Peng 2 He Zongming 3 Chen Guangshui 1 (11 College of Geography Science, ujian Normal University uzhou ; 21 College of Life Science, Xiamen University Xiamen ; 31 orestry College of ujian Agriculture and orestry University uzhou350002) Abstract : During the past decades, large2scale natural forests had been converted to fast2growing and high yield commercial plantations to meet the demands for timber, fuel material, and other forest products. Some silvicultural measures, such as planting pure stands, clear cutting and slash burning, were widely applied during this conversion. Yield decline and land deterioration in such disturbed ecosystems had become serious. In this context, the ecological comparisons between natural forests and plantations have special implications for sustainable management. Coarse woody debris ( CWD) as an important pool of carbon and nutrients also plays a substantial role in several ecological processes in forest ecosystems. However, few studies on CWD have been conducted in natural and planted forests under same climatic and edaphic conditions in subtropical China. The standing crop and seasonal dynamics of CWD, its carbon and nutrient stocks were studied in a natural forest of Castanopsis kawakamii (N) and adjacent plantations of C. kawakamii ( CK) and Chinese ir( Cunninghamia lanceolata, C) in Sanming, ujian, China. CWD masses were 1132 t hm - 2 in the N, 0146 t hm - 2 in the CK and 0123 t hm - 2 in the C respectively. The standing crop of CWD in three forests showed similar seasonal trend as follows : summer > winter > autumn > spring. Carbon storage in CWD of the N was 0178 t hm - 2, being 4111 times and 7109 times as much as that of the CK and the C, respectively. Significant difference in C stocks of CWD was found between N and CK (or C) ( P < 0105). Nutrient storage in CWD ranged from kg hm - 2 in the N to 0195 kg hm - 2 in the C. The amounts of N, P, K, Ca and Mg storage were the highest in CWD of the N. The results of this study demonstrate that the natural forest has a greater capability for maintaining site productivity than plantations due to higher CWD mass coupled with greater carbon and nutrient pools. Therefore, conservation of the natural forest is recommended as a practical measure in forest management to realize sustainable development of forestry in mountainous areas of southern China. Key words : coarse woody debris ; carbon pool ; nutrient pool ; Castanopsis kawakamii ; forest ; plantation Cunninghamia lanceolata ; natural,,, : ( ) ;

2 ) ( Castanopsis kawakamii) ( 150 ) (700 hm 2 ), 1986) 20 60, ( Cunninghamia lanceolata) ( okienia hodginsii) ( Ormosia xylocarpa), ( ),, 1986 ;, 1992 ;1998),,,,,, 1992 ; Sollins, 1987),, (, 1993), 1 ( N, E),, 300 m ;, 1911, mm( 3 8 ), mm, 81 %, 300 d ;, 1 m 1966,, , hm , m 20 m, 31, 1986 ;, 1998) 3 ( > 18 m, m 6 12 m), ( Pinus massoniana) ( Schima superba) ( Lithocarpus glaber) ( Symplocos caudata ) ( Machilus pauhoi ) ( Randia cochinchinensis), ( 0180 ) 2 ( < 6 m < 2 m), ( Ardisia crispa) ( Vaccinium carlesii) ( Tricalysia dubia) ( Ilex pubescens), 45 %, ( Woodwardia japonica), ( Dicranopteris dichotoma),, 30, ( Maesa japonica) ( Mussaenda pubescens) ( Millettia reticulata),, 35, ( icus hirta) ( Rubus palmatus) ( Angiopteris fokiensis) ( Blechnum orientale) , 10 m 1 4 m 4 m, 5, 15 ( ) 105, 85, 1 mm, 212 -, KDN - ( ), KDN - C ( ) N, P, K,AA Ca Mg - C (, 2000) 213 SPSS(1110) T ( P < 0105)

3 3 : 9 1 Tab. 1 Stand characteristics and soil properties in the N, CK and C Parameters orest type N CK C Stand characteristics Canopy coverageπ% Mean tree heightπm Mean tree diameter at breast heightπcm Stand densityπ(stem hm - 2 ) Stand volumeπ(m 3 hm - 2 ) Biomass of shrub layerπ(t hm - 2 ) Biomass of herb layerπ(t hm - 2 ) Thickness of forest floorπcm Soil (top 0 20 cm) properties Bulk densityπ(g cm - 3 ) Water contentπ Organic matterπ N Total N Π P Total P Π N Hydrolyzable N Π(mg kg - 1 ) P Available P Π(mg kg - 1 ) K Available KΠ(mg kg - 1 ) N : Castanopsis kawakamii natural forest ; CK: C. kawakamii plantation ; C : Chinese ir plantation. C. kawakamii is only involved in the N. The same below Tab. 2 Reserves of coarse woody debris in three forests t hm orest type L Layer N CK C L a b b a b c ( P < 0105), 2 L a b b L ( P < 0105, n = 15), ( P > 0105) Different letters on the same row indicate significant differences at P < 0105, n = 151 The same below t hm - 2, L t hm - 2, t hm - 2 ( 2) > > > 3 ( 1), ( P < 0105) 312 C L, C C ( 3) C t hm - 2, C 2 ( P < 0105), C L ;3 L C C % % %, C C % % %( 3) 313 N CK C 1 ig. 1 Seasonal dynamics of standing crop of coarse woody debris N P K Ca Mg

4 10 41 N K Ca, P Mg ( 4),, N > Ca > K> Mg > P CΠN L >, CΠN N < CK< C Layer L L C Tab. 3 Concentrations and reserves of organic carbon of coarse woody debris in three forests a a N CK C a a a a a b b b a a b c b ( P < 0105) N P K Ca Mg kg hm - 2, , kg hm - 2, ( 4) 4,3 :N > Ca > K> Mg > P 4 411, t hm - 2, Olympic ( Pseudotsuga sinensis) ( Tsuga chinensis), 537 t hm - 2 ; ( Sequoiadendron giganteum) - ( Pinus koraiensis), 200 t hm - 2, 8 50 t hm - 2, ( Cyclobalanopsis glauca) ( Betula sp. ), t hm - 2, 20 t hm - 2 ( Harmon, 1986),,,,, (Hely et al., 2000),,,3 ( 1),, 412, kg 1992) (0 3 m) 3 % 6 %(Job ggy et al., 2000),,, ( ) ( Gaudinski et al., 2000 ; Trumbore, 2000) 3, 1991), 50 %,,

5 3 : 11, t hm - 2, % 5178 % 4182 %, Andrews 1992),, 413, ( ),,, 1992),, CΠN ( 4), (Harmon, 1986),, (, 1993) L CΠN, C N,, ( Castanopsis eyrei) 1992 ;, 1996), orest type Layer 4 3 Tab. 4 Nutrient concentrations and reserves of coarse woody debris in three forests N P K Ca Mg N P K Ca Mg Subtotal N L L a a a a a a CK L L b b b b b b C 1 L L c c c,Harmon M E , 3 (2) : , , 10(1) : c c, :.. :, c,,, , 20(2) : , , 10(4) : ,, , 18(2) : :,, , 7(3) : : Gaudinski, J B, Trumbore S E, Davidson E A, et al Soil carbon cycling in a temperate forest : radiocarbon2based estimates of residence times, sequestration rates, and partitioning of fluxes. Biogeochemistry, 51 :33-69 Harmon M E Ecology of coarse woody debris in Temperate Ecosystems. Adv Eco Res, 15 : Hely C, Bergeron Y, lannigan M D Coarse woody debris in the southeastern Canadian boreal forest : composition and load variations in relation to stand replacement. Can J or Res, 30 : Job ggy E G, Jackson R B The vertical distribution of soil organic carbon and its relation to climate and vegetation. Ecol Appl, 10 (2) : Sollins P Patterns of log decay in old-growth Douglas-fir forests. Can J or Res, 17 : Trumbore S E Age of soil organic matter and soil respiration : radiocarbon constraints on belowground C dynamics. Ecol Appl, 10 (2) :