Research Article

Influence of Long-Term Thinning on the Biomass Carbon and Soil Respiration in a Larch (Larix gmelinii) Forest in Northeastern China

Table 1

Long-term thinning effects on the growth and biomass C accumulation of species found in larch plantations. Values in parentheses are standard deviations.

ParametersTreatmentArbor layerShrubs and saplingsTotal
Larix gmelinii Betula platyphylla Fraxinus mandshurica Arbor total

Diameter (cm)Thinned21.7 (4.7)b19.2 (2.4)a18.1 (9.2)a1.34 (1.57)a
Unthinned 18.0 (5.3)a21.8 (3.8)a14.2 (6.7)a2.12 (2.06)a
Density (No·hm−2)*Thinned950 (45)a38 (15)a63 (16)a1050 (40)a10500 (550)a
Unthinned 1063 (67)b100 (18)b100 (24)b1263 (60)b7700 (450)b
Mean height (m)Thinned18.5 (1.9)a17.5 (3.4)a16.6 (6.5)a1.68 (1.22)a
Unthinned 17.8 (2.0)a18.1 (4.3)a13.8 (6.8)a2.08 (1.46)a
Biomass (Mg·ha−1)Thinned216.0 (12.1)a7.1 (3.1)b5.0 (1.3)b231.1 (13.2)a1.52 (0.73)a232.6
Unthinned 156.4 (13.1)b15.1 (4.2)a12.9 (3.2)a191.2 (15.1)b2.51 (0.63)a193.7
Biomass C (g C m−2)Thinned10800 (605)a355 (155)a250 (38)b11555 (660)a76 (36)a11630
Unthinned 7820 (655)b756 (210)b646 (160)a9560 (755)b126 (31)a9686
Difference
(g C m−2)
Thinned-Unthinned2980−400−3961994−501944
Annual C change (g C m−2 yr−1)#114.6−15.4−15.276.7−1.974.8

Tree density for arbor layer species was calculated for trees of DBH > 10 cm, while for shrubs and saplings it was calculated for plants of basal diameter > 0.4 cm. #The annual C change is the difference between thinned and unthinned divided by the total thinning duration (26 years).