Vanninen Petteri, Mäkelä Annikki
Department of Forest Ecology, P.O. Box, FIN-00014 Helsinki University, Finland.
Tree Physiol. 2005 Jan;25(1):17-30. doi: 10.1093/treephys/25.1.17.
Time series of carbon fluxes in individual Scots pine (Pinus sylvestris L.) trees were constructed based on biomass measurements and information about component-specific turnover and respiration rates. Foliage, branch, stem sapwood, heartwood and bark components of aboveground biomass were measured in 117 trees sampled from 17 stands varying in age, density and site fertility. A subsample of 32 trees was measured for belowground biomass excluding fine roots. Biomass of fine roots was estimated from the results of an earlier study. Statistical models were constructed to predict dry mass (DW) of components from tree height and basal area, and time derivatives of these models were used to estimate biomass increments from height growth and basal area growth. Biomass growth (G) was estimated by adding estimated biomass turnover rates to increments, and gross photosynthetic production (P) was estimated by adding estimated component respiration rates to growth. The method, which predicts the time course of G, P and biomass increment in individual trees as functions of height growth and basal area growth, was applied to eight example trees representing different dominance positions and site fertilities. Estimated G and P of the example trees varied with competition, site fertility and tree height, reaching maximum values of 22 and 43 kg(DW) year(-1), respectively. The site types did not show marked differences in productivity of trees of the same height, although height growth was greater on the fertile site. The G:P ratio decreased with tree height from 65 to 45%. Growth allocation to needles and branches increased with increasing dominance, whereas growth allocation to the stem decreased. Growth allocation to branches decreased and growth allocation to coarse roots increased with increasing tree size. Trees at the poor site allocated 49% more to fine roots than trees at the fertile site. The belowground parts accounted for 25 to 55% of annual G, increasing with tree size and decreasing with site fertility. Annual G and P per unit needle mass varied over the ranges 1.9-2.4 and 3.5-4.0 kg(DW) kg(-1), respectively. The relationship between P and needle mass in the example trees was linear and relatively independent of competition, site fertility and age.
基于生物量测量以及各组分特定周转和呼吸速率的信息，构建了苏格兰松（Pinus sylvestris L.）单株树木碳通量的时间序列。从17个年龄、密度和立地肥力各异的林分中选取了117株树木，测量了地上生物量的叶片、树枝、树干边材、心材和树皮组分。对32株树木的地下生物量（不包括细根）进行了测量。细根生物量根据早期研究结果估算。构建了统计模型，根据树高和胸径预测各组分的干质量（DW），并利用这些模型的时间导数，根据树高生长和胸径生长估算生物量增量。通过将估算的生物量周转率与增量相加来估算生物量生长（G），并通过将估算的组分呼吸速率与生长量相加来估算总光合产量（P）。该方法将单株树木中G、P和生物量增量的时间进程预测为树高生长和胸径生长的函数，并应用于代表不同优势地位和立地肥力的8株示例树木。示例树木估算的G和P随竞争、立地肥力和树高而变化，最大值分别达到22和43 kg（DW）年⁻¹。尽管在肥沃立地上树高生长更大，但相同高度树木的生产力在不同立地类型间未表现出明显差异。G:P比值随树高从65%降至45%。随着优势度增加，分配给针叶和树枝的生长增加，而分配给树干的生长减少。随着树木大小增加，分配给树枝的生长减少，分配给粗根的生长增加。贫瘠立地上的树木分配给细根的比例比肥沃立地上的树木多49%。地下部分占年G的25%至55%，随树木大小增加而增加，随立地肥力降低而减少。示例树木中单位针叶质量的年G和P分别在1.9 - 2.4和3.5 - 4.0 kg（DW）kg⁻¹范围内变化。示例树木中P与针叶质量之间的关系呈线性，且相对独立于竞争、立地肥力和年龄。
