Chinese Forest Research Articles

Developing camera-trapping protocols for wildlife monitoring in Chinese forests

Developing camera-trapping protocols for wildlife monitoring in Chinese forests

黄土丘陵区油松人工林生态系统碳密度及其分配

Currently,most studies related to carbon storage focus on the arbor layer; however,few in-depth studies have analyzed the variations in carbon storage allocation of different layers of plant communities with different stand ages. To estimate carbon density of Pinus tabulaeformis plantation ecosystems for different stand ages more accurately,we tracked 9-, 23-,33- and 47-year-old P. tabulaeformis plantations in the Hilly Loess Plateau region of China and studied the carbon content in plant organs,litter and soil,as well as the carbon storage and its allocation in different layers. By analyzing carbon sequestration characteristics of P. tabulaeformis plantations at different age stages,this paper provides a theoretical basis of evaluating the function of carbon sinks in P. tabulaeformis plantations during forest management. In addition,thecarbon density of the forest ecosystems was measured and evaluated based on "The Research Norms of Chinese Forest Ecosystem Carbon Sequestration,Rate and Potential",which provides a basis for comparative study of cross-regional forest types. The main results were as follows.( 1) Average biomass in the different components of the studied forest ecosystems were in the order of: arbor layer( 76. 12 t / hm2) litter layer( 14. 56 t/hm2) undergrowth vegetation layer( combined herb and shrub layer vegetation; 3. 66 t / hm2). The biomass of the arbor layer of P. tabulaeformis increased with stand age. The Pinus arbor organ biomass was as follows: stem accounted for the largest share,followed by leaves and roots,the contribution of branches and bark were minimal. Undergrowth biomass first increased then decreased with increasing tree age,while litterfall biomass increased with tree age. The biomasses of shrub organs were markedly different,which showed that biomass of branches roots leaves. In the herb layer,the above-ground portion of biomass was significantly greater than the underground portion.( 2) The average carbon content was 50. 2% for P. tabulaeformis and for different organs the order was leaves( 53. 3%) branches( 51. 4%) bark( 50. 6%) stems( 49. 8%) roots( 47. 3%). The amount of carbon stored in the shrub,herb and litter layers was 44. 5%,43. 8% and 40. 6%,respectively. Shrub carbon content of various organs was in the order of branches( 46. 0%) leaves( 44. 8%) roots( 42. 5%). The carbon content of herbs was greater in the above-ground portion( 45. 2%) than in the underground portion( 40. 2%). Forest age had no significant effect on the carbon content of arbor organs. The carbon content of different shrub organs was significantly different for each herb species. The carbon content of soil( 0—100 cm) was between 0. 3 and 2. 7% and had an obvious vertical distribution characteristic: the surface soil layer had a higher carbon content and carbon content gradually decreased as soil depth increased.( 3) Forest age was a dominant factor affecting the carbon density of the P. tabulaeformis forest community. The carbon density of 9-,23-,33- and 47-year-old P. tabulaeformis forests was 70. 49,100. 94,167. 09 and 144. 93 t / hm2, respectively. Carbon density in different components of the studied forest ecosystems was in the order of: soil layer vegetation layer litter layer. The proportion of vegetation carbon density increased with increasing tree age continually, whereas that of soil carbon density had the opposite pattern. 9-,23-,33- and 47-year-old P. tabulaeformis forest arbor layer carbon densities increased with stand age( 0. 90,26. 56,59. 73 and 60. 20 t / hm2,respectively),as did carbon density in the litter layer. The vegetation layer and soil layer carbon density first increased and then decreased with increasing stand age.

Spatial characteristics in decomposition rate of foliar litter and controlling factors in Chinese forest ecosystems

Aims We aim to construct a national database for decomposition rate of forest foliar litter and to investigate the effects of controlling factors concerning geography (i.e. latitude, longitude, and altitude), climate (i.e. mean annual temperature and mean annual precipitation), and litter quality (i.e. the concentrations of N, P, K, and lignin, C:N ratio, and lignin:N ratio) on litter decomposition. Methods We compiled a large dataset on decomposition constant (i.e. k value, which indicates the rate of litter decomposition) for foliar litter in Chinese forest ecosystems covering 74 study sites, and conducted simple and multiple regression analyses to explore the relationships of the k value with the controlling factors at the national scale. Important findings The k value showed a tendency to decrease with latitude, longitude, altitude, lignin content, C:N, and lignin:N of litter, and to increase with mean annual temperature, mean annual precipitation, and litter nutrient concentrations (N, P and K) at the national scale. Single factors such as climate, litter quality, and geographic variable only explained 0.1%–30.3% of the variation in the rate of litter decomposition. However, a combination of climatic factors (mean annual temperature and mean annual precipitation) and latitude accounted for 34.1% of the variation in the rate of litter decomposition. Similarly, a combination of N, K, lignin, and lignin:N accounted for 21.7% of the variation in the rate of litter decomposition. Altitude, mean annual temperature, mean annual precipitation, N, K, and lignin:N collectively accounted for 74.4% of the variation in the rate of litter decomposition. Our results suggest that climate is the most important regulator of litter decomposition at the 530 植物生态学报 Chinese Journal of Plant Ecology 2014, 38 (6): 529–539 www.plant-ecology.com national scale and that the effects of litter quality is relatively small compared to climate.

Anthropogenic disturbance shapes phylogenetic and functional tree community structure in a subtropical forest

Forests across the world are increasingly affected by human activities, with unmanaged forests often in early- and mid-successional phases after anthropogenic disturbances. In consequence, it is important to obtain a better understanding of these successional dynamics and their implications for the functioning of forest ecosystems. Here, we investigate this issue for a highly diverse subtropical forest in China, as it is particularly relevant here. China naturally harbors large forested areas and much forest biodiversity, but its forests are also subject to strong anthropogenic pressures, with only 2% of its forest remaining undisturbed. We assess how anthropogenic disturbance shapes two important aspects of forest biodiversity, namely phylogenetic and functional community structure. Comparing plots that have not been disturbed within the last 100years, plots clear-cut ∼50years ago, and plots clear-cut ∼50years ago and then selectively cut ∼20years ago, we find that the abundant gymnosperm species which are important pioneer species in southern China strongly affect phylogenetic structure, causing over-dispersion among large stems in disturbed stands. A tendency for decreasingly clumped phylogenetic structure over succession when considering only angiosperms may reflect an initial filtering by disturbance whose legacy decreases during succession. Multi-trait functional structure, which was not significantly affected by gymnosperms, has similar patterns to the phylogenetic structure without gymnosperms. Phylogenetic and functional structure differs among stem size classes, but with partially divergent trends. Functional structure is more strongly linked to a disturbance indicator, the proportion of light-demanding species, than phylogenetic structure. Our results illustrate that past tree harvesting has left strong legacies in the phylogenetic and functional structure of tree stands in a highly diverse southern Chinese forest and thus may also shape their functioning.

The Gain or Loss of Ecosystem Services in the Changbai Mountain Natural Reserves under the Policy Intervention

Based on the published studies and the data from multiple-year consecutive observation of the Long Term Ecological Research Station affiliated to the Chinese Forest Ecosystem Research Network (CFERN), the ecosystem services of carbon fixation and oxygen release, water conservation, soil conservation and nutrient accumulation of the Changbai Mountain Natural Reserve (CMNR), PR China, from 1985 to 1997 were evaluated using the Specifications for Assessment of Forest Ecosystem Services in China (LY/T17212008) promulgated by State Forestry Administration of China. The results show that the loss of ecosystem service value in CMNR was 59.76 million dollar under the policy intervention. These ecosystem services show trade-off/synergistic relationship. Carbon fixation and oxygen release, water conservation and soil conservation decreased greatly, while nutrient accumulation slightly increased from 1985 to 1997. This research could provide a scientific basis for policy-making in sustainable development of natural reserves.

Tree Biomass Estimation of Chinese fir (Cunninghamia lanceolata) Based on Bayesian Method

Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) is the most important conifer species for timber production with huge distribution area in southern China. Accurate estimation of biomass is required for accounting and monitoring Chinese forest carbon stocking. In the study, allometric equation was used to analyze tree biomass of Chinese fir. The common methods for estimating allometric model have taken the classical approach based on the frequency interpretation of probability. However, many different biotic and abiotic factors introduce variability in Chinese fir biomass model, suggesting that parameters of biomass model are better represented by probability distributions rather than fixed values as classical method. To deal with the problem, Bayesian method was used for estimating Chinese fir biomass model. In the Bayesian framework, two priors were introduced: non-informative priors and informative priors. For informative priors, 32 biomass equations of Chinese fir were collected from published literature in the paper. The parameter distributions from published literature were regarded as prior distributions in Bayesian model for estimating Chinese fir biomass. Therefore, the Bayesian method with informative priors was better than non-informative priors and classical method, which provides a reasonable method for estimating Chinese fir biomass.

Chinese forest policy reforms after 1998: the case of the Natural Forest Protection Program and the Slope Land Conversion Program

SUMMARY In this article we discuss the two largest reforestation and forest conservation programmes in China, the Natural Forest Protection Programme (NFPP), and the Slope Land Conversion Programme (SLCP, also called Grain for Green), introduced in 1998. The NFPP reformed the state forest enterprises to reduce deforestation, increase the amount of forestland to be protected, and increase the sustainability of logging, while improving their financial viability. The SLCP reformed collective (i.e. private) forests in the villages, by compensating farmers for retiring marginal (mostly slope) land. Together, these two programmes are the largest reforestation programmes in the world, in term of people affected (over 125 million people), land reforested or protected (over 150 million ha), and budget (over 800 billion yuan between 1998 and 2020). We review these two programmes within the broad political and socio-economic conditions of the country during these years.

Application of Gash analytical model and parameterized Fan model to estimate canopy interception of a Chinese red pine forest

Loss of precipitation by canopy interception constitutes a substantial portion of the water budget in a forested ecosystem, and accurate models to simulate canopy interception are critical for effective management of forest water resources. We modeled the canopy interception of an evergreen Chinese red pine (Pinus tabulaeformis) forest using the Gash analytical model and the parameterized empirical Fan model and compared the modeled results with directly measured data. Based on 100 rainfall events between 2006 and 2008, the estimated canopy interception ratio was 35.9 % from the Gash model and 53.6 % from the Fan model, compared to 33.2 % from the direct measurement. The differences between measured and modeled values from the Gash model ranged from −0.3 to +7.1 % for different rainfall amounts and from +1.9 to +3.2 % for different years. The Fan model satisfactorily simulated interception for large rainfall events (>50 mm) with differences from −3.4 to +1.3 %, but substantially overestimated interception loss for smaller rainfall events (+21.2 to +37.2 %). The Gash analytical model adequately simulated the canopy interception of Chinese red pine forest. The parameterized Fan model compared favorably to the Gash model in simplicity but not in precision. The Fan model required only incidental precipitation data to run after parameterization, but substantial improvement in modeling precision is needed before it can be used for this forest.

Diversity of Methanotrophic Bacteria Community between Different Development Stages in Chinese Temperate Forest

The method of terminal restriction fragment length polymorphism (T-RFLP) was used to study the community structures and diversities of aerobic methanotrophs by the key functional genes pmoA in the forest land soils of Changbai Mountains in China. And the effects of soil factors on them were also evaluated, and then the mechanism of microbiological communities in forest land soils response to the forest succession were discussed. The results showed that the diversity indices of aerobic methanotrophs were higher, and community structures appeared more complicated at the later plots. Their similarity coefficients gradually declined from the middle of the forest succession to the adjacent forest, indicating communities dynamic succession. During succession process, soil moisture and organic matter content had significant influence on it. The microbial communities were under the stress of succession process, which led to more emission of other greenhouse-gas from forest soils.

Regional constraints on leaf physiognomy and precipitation regression models: a case study from China

The relationship between leaf physiognomy and precipitation has been explored worldwide in regions under different climate conditions. Unlike the linear relationship established between the percentage of woody dicot species with entire margins and mean annual temperature, precipitation has been reported to correlate to different leaf physiognomic characters depending on the region where the correlation is studied. To investigate if precipitation can be calculated from leaf physiognomic characters on the basis of regional sample sites, data from 50 mesic to humid forests in China were analyzed in this study. With data from Chinese forests, the leaf-area analysis based on linear regression between natural logarithms of leaf size and mean annual precipitation (MAP) shows no significant correlation. Both single and multiple linear regression analyses fail to confirm the correlation between leaf physiognomy and precipitation, which may result from the similarity of modern spatial distribution of temperature and precipitation in China. Our results show that, due to variations in climatic conditions among sampling regions, leaf physiognomic characters that correlate to precipitation are not consistent worldwide, and applications of models without considering regional constraints could mislead our understanding of palaeoclimate. Therefore, when choosing a leaf physiognomic model for palaeoclimate reconstructions, it is important to determine if the leaf physiognomy of the palaeoflora lies within the leaf physiognomic spectrum of the model used.

Within-twig leaf distribution patterns differ among plant life-forms in a subtropical Chinese forest

In theory, plants can alter the distribution of leaves along the lengths of their twigs (i.e., within-twig leaf distribution patterns) to optimize light interception in the context of the architectures of their leaves, branches and canopies. We hypothesized that (i) among canopy tree species sharing similar light environments, deciduous trees will have more evenly spaced within-twig leaf distribution patterns compared with evergreen trees (because deciduous species tend to higher metabolic demands than evergreen species and hence require more light), and that (ii) shade-adapted evergreen species will have more evenly spaced patterns compared with sun-adapted evergreen ones (because shade-adapted species are generally light-limited). We tested these hypotheses by measuring morphological traits (i.e., internode length, leaf area, lamina mass per area, LMA; and leaf and twig inclination angles to the horizontal) and physiological traits (i.e., light-saturated net photosynthetic rates, Amax; light saturation points, LSP; and light compensation points, LCP), and calculated the 'evenness' of within-twig leaf distribution patterns as the coefficient of variation (CV; the higher the CV, the less evenly spaced leaves) of within-twig internode length for 9 deciduous canopy tree species, 15 evergreen canopy tree species, 8 shade-adapted evergreen shrub species and 12 sun-adapted evergreen shrub species in a subtropical broad-leaved rainforest in eastern China. Coefficient of variation was positively correlated with large LMA and large leaf and twig inclination angles, which collectively specify a typical trait combination adaptive to low light interception, as indicated by both ordinary regression and phylogenetic generalized least squares analyses. These relationships were also valid within the evergreen tree species group (which had the largest sample size). Consistent with our hypothesis, in the canopy layer, deciduous species (which were characterized by high LCP, LSP and Amax) had more even leaf distribution patterns than evergreen species (which had low LCP, LSP and Amax); shade-adapted evergreen species had more even leaf distribution patterns than sun-adapted evergreen species. We propose that the leaf distribution pattern (i.e., 'evenness' CV, which is an easily measured functional trait) can be used to distinguish among life-forms in communities similar to the one examined in this study.

The environment and space, not phylogeny, determine trait dispersion in a subtropical forest

Summary A central aim of forest ecologists is to quantify the relative importance of different community assembly mechanisms in tropical and subtropical tree communities. Recent work in this field has focused on the importance of functional trait similarity and abiotic filtering. While important, none of this work has simultaneously: linked these trait dispersion patterns to the underlying abiotic environment, considered dispersal limitation and quantified the degree to which patterns of trait dispersion may be explained simply by shared ancestry. Here we use data from a subtropical Chinese forest to accomplish this goal. We first examine the trait dispersion (leaf area, specific leaf area, seed mass, wood density, maximum height and five traits together) on local scales by comparing the observed trait dispersion pattern to that expected from a null model. Then we use a variance partitioning approach to examine the degree to which spatial proximity, environmental similarity or the phylogenetic dispersion of the species determine the observed trait dispersion. The results show that, on local scales, trait dispersion is often non‐randomly filtered. Further the widespread trait clustering observed is largely explained by the environment and space, while the phylogenetic dispersion of species in a sample explains relatively little. This result further underscores that inferring an assembly mechanism from a pattern of phylogenetic dispersion is tenuous. The work is important in that it is the first to partition the variation in tree trait diversity into its spatial, environmental and phylogenetic components and that it demonstrates that functional trait data often lack enough phylogenetic signal on local scales to confidently link patterns of trait and phylogenetic dispersion. Ultimately, the findings suggest a strong role for abiotic filtering and dispersal limitation during community assembly on local spatial scales and that shared evolutionary history plays a relatively small role.

基于LULUCF温室气体清单编制的浙江省杉木林生物量换算因子

Taking Chinese fir(Cunninghamia lanceolata(Lamb.Hook.)) forest as the subjects of this study,95 sample plots were selected from 12 counties in CFI system(2009) of Zhejiang province.According to the average trees of 95 plots,95 analytic trees were selected outside the sample plots but similar with them,and simultaneous equations of DBH-H equation and biomass model were established.Then,we compared the estimation outputs of 20 biomass models,calculated the ratio of stand biomass and stand volume which is exactly BEF,established the relationship between stand stock and BEF.According to Zhejiang CFI system 2009(eighth),we calculated Chinese fir forest BEF in Zhejiang province is 0.7453 t/m3,and Chinese fir forest total biomass is 37.2154 million tons,uncertainty for 5.739%.Finally,based on IPCC(1996) carbon density default value(0.50),1 m3 growth of Chinese fir forest absorbs CO2 1.3663 t.

寒温针叶林土壤呼吸作用的时空特征

Boreal forest is naturally situated between 45° and 70° north latitude,where temperature increases strongly. With the largest soil carbon pool in the world,boreal forest becomes an important research region concerning global climate change and carbon cycle. The variable patterns of soil respiration in both temporal and spatial scales were measured with Li-6400 portable photosynthesis system in Chinese boreal forest ecosystem( 51° 47' N,123°01' E). The results showed that the diurnal dynamics of soil respiration was one-humped curve,and the maximum occurred at 16: 00,similar to the dynamics of soil temperature at 5 cm depth. Soil respiration increased from June and peaked in August( 8.19 and 6.89 μmol CO 2 m-2s-1in 2006 and in 2007,respectively),then decreased and dropped down only 0.61 μmol CO 2 m-2s-1in October when air temperature was about 0 ℃. The diurnal and seasonal variations of soil respiration related more to soil temperature than to air temperature. To study on spatial heterogeneity of soil respiration in Chinese boreal forest ecosystem,40 circular plots( 10 cm in diameter) were set with 5 columns and 8 rows,and the interval was 2 m. The averages of variation ranges of soil respiration ranged from 4.96 μmol CO 2 m-2s-1to 5.97 μmol CO 2 m-2s-1among 40 circular plots,larger or close to the averages of diurnal dynamics ranging from 2.88 μmol CO 2 m-2s-1to 5.31 μmol CO 2 m-2s-1,and smaller than the averages of seasonal dynamics ranging from 6.48 μmol CO 2 m-2s-1to 7.38 μmol CO 2 m-2s-1. Soil respiration showed great variability among 40 circular plots,and the coefficients of variation were 35.5%,27.6% and 23. 0% on 3: 00 am,7: 00 am and 11: 00 am,respectively. When soil respiration of the close plots was averaged,their coefficients of variation decreased with the repeated plots increasing. The coefficients of variation with 3 repeats were 27. 0%,16.8% and 13.0% on 3: 00 am,7: 00 am and 11: 00 am,respectively. The coefficients of variation with 6 repeats were 22.8%,11.1% and 11.8% on 3: 00 am, 7: 00 am and 11: 00 am,respectively,close to the smallest coefficients of variation with 7—10 repeats. Therefore,soil respiration should be measured with 6 repeats of circular plots( 10 cm in diameter) in this research region. Similar spatial heterogeneities were found on root and litter biomass among 40 circular plots,the coefficients of variation from large to small were 103.8% of coarse root,60.3% of total root,47.1% of litter and 32.1% of fine root. The spatial correlation of soil respiration was best with the fine root( R2= 0. 322—0. 396),indicating that the spatial heterogeneity of soil respiration could be mainly induced with fine root.

Thermal Decomposition Extent of Duff due to Surface Forest Fire

In ground fires, duff is thermally decomposed and smoldering combustion occurs. Duff is also partially decomposed by surface fire heating and the decomposition percentage is a clue to surface fire severity assessment. This article investigates thermal oxidative decomposition characteristics of Northeast Chinese forest duff samples, with and without surface fire heating effect, by thermogravimetry. The curves of all duff samples showed four stages, i.e. moisture evaporation, duff devolatilization, char oxidation and nearly-invisible inorganic minerals decomposition. The effect of surface fire heating was estimated by comparing the mass loss ratio of the devolatilization stage to the char oxidation stage and it was found that nearly 27.4% of original duff was decomposed by surface fire heating.

A population survey of Beauveria bassiana in the microhabitat of the red turpentine beetle, Dendroctonus valens, in Chinese pine forests

Field survey of the entomopathogenic fungus Beauveria bassiana in association with the red turpentine beetle, Dendroctonus valens, was undertaken in three pine plantations in Northern China. In total, 88 strains of B. bassiana sensu lato were isolated from the soil, bark, beetle frass, living adult and cadaver samples and soil was proved to be an important inoculum reservoir for fungal entomopathogens. Of these, 77 isolates were included for genetic diversity analysis by PCR for inter-simple sequence repeats (ISSR). Genetic diversity and population structure analysis of the isolates from three sites and five niches demonstrated high genetic diversity and heterogeneity between and/or within populations. Wright's statistics revealed a high gene flow rate (4.529) among the three populations, especially among the soil-derived isolate subpopulations. Low variation was mainly caused (94.8%) by variation among different substrates, suggesting the importance of microhabitat substrates on genetic diversity of B. bassiana. Phylogenetic variation was not associated with geographic distance.

Functional traits of denitrification in a subtropical forest catchment in China with high atmogenic N deposition

Subtropical forests in SW China, receiving high nitrogen (N) deposition, have been reported to show high N retention. N removal by denitrification may be one important process favored by warm and wet soils during monsoonal summer when most of the atmogenic N input occurs. Due to low pH soils which are common in this region, N removal by denitrification may entail substantial N2O emissions. In this study, we explored intrinsic denitrification characteristics of soils from different landscape elements of a forested headwater catchment in SW China (Tieshanping, Chongqing). Laboratory incubations were used to measure instantaneous denitrification rates, apparent specific denitrifier growth rates, denitrification product stoichiometries (N2O/(N2O + N2)) and response to carbon-addition as a function of soil depth and landscape position. The results revealed that potential denitrification and denitrifier growth rates were highest in top soils along a hill slope, and decreased strongly with soil depth due to C-limitation. A hydrologically connected, colluvial groundwater discharge zone showed equally high instantaneous denitrification rates which were more equally distributed with depth. Denitrifying communities in the top horizons of the hill slope were less efficient in expressing N2O reductase in response to anoxia resulting in higher N2O/(N2 + N2O) product ratios than found in soils of the groundwater discharge zone, suggesting that a significant share of the deposited N can be lost as N2O from the hill slopes. Differences in denitrification traits appeared to be linked to eco-hydrological conditions in the two landscape elements and to substrate availability along the hydrological flowpath. Our study supports the notion that denitrification plays an important role for observed N removal in SW Chinese forest ecosystems and illustrates how habitat functions constrain the amount of N2O emitted during N removal.

‘Making Green the Motherland’: greening the Chinese socialist undertaking (1949–1978)

‘Making Green the Motherland’: greening the Chinese socialist undertaking (1949–1978)

Environmental Impact Assessment of Wood Pulp from a Eucalyptus Plantation in South China by Using Life-Cycle Analysis

Abstract This exploratory study evaluated the environmental impacts associated with Bleached Eucalyptus Kraft Pulp supplied from a eucalyptus plantation in South China by applying the life-cycle analysis approach. The system boundary was defined by a “cradle-to-gate” perspective including the forest subsystem and the pulp mill subsystem. Key processes were investigated and site-specific data were collected during 2009 and 2010 through field trips to a leading plantation operator and a representative pulp mill in China. Umberto 5.5 software was used to conduct a life-cycle inventory, which compiled all the inputs and outputs of the examined system. Hot-spot processes with high environmental burdens were identified with regard to selected impact categories of global warming, acidification, eutrophication, nonrenewable resources depletion, and human toxicity. According to the findings of this study, the forest subsystem showed significant contributions to the total environmentaltable4 burdens in almost all impact categories, mainly due to the application of fertilizers in eucalyptus plantation management. The study discovered that while the pulp mill subsystem was the primary contributor to global warming impacts, the upstream processes of raw materials and energy production accounted for more than half of the impacts of acidification, human toxicity, and resources depletion. Therefore, eucalyptus plantation management and the supply of raw materials and energy in pulp mills in China are concluded to be concerns for future development. These findings may help the Chinese forest industry and pulp industry achieve better environmental performance toward sustainable development.

Identification and Behavioral Evaluation of Sex Pheromone Components of the Chinese Pine Caterpillar Moth, Dendrolimus tabulaeformis

BackgroundThe Chinese pine caterpillar moth, Dendrolimus tabulaeformis Tsai and Liu (Lepidoptera: Lasiocampidae) is the most important defoliator of coniferous trees in northern China. Outbreaks occur over enormous areas and often lead to the death of forests during 2–3 successive years of defoliation. The sex pheromone of D. tabulaeformis was investigated to define its chemistry and behavioral activity.Methodology/Principal FindingsSex pheromone was collected from calling female D. tabulaeformis by headspace solid phase microextraction (SPME) and by solvent extraction of pheromone glands. Extracts were analyzed by coupled gas chromatography/mass spectrometry (GC-MS) and coupled GC-electroantennographic detection (GC-EAD), using antennae from male moths. Five components from the extracts elicited antennal responses. These compounds were identified by a combination of retention indices, electron impact mass spectral matches, and derivatization as (Z)-5-dodecenyl acetate (Z5-12:OAc), (Z)-5-dodecenyl alcohol (Z5-12:OH), (5Z,7E)-5,7-dodecadien-1-yl acetate (Z5,E7-12:OAc), (5Z,7E)-5,7-dodecadien-1-yl propionate (Z5,E7-12:OPr), and (5Z,7E)-5,7-dodecadien-1-ol (Z5,E7-12:OH). Behavioral assays showed that male D. tabulaeformis strongly discriminated against incomplete and aberrant blend ratios. The correct ratio of Z5,E7-12:OAc, Z5,E7-12:OH, and Z5,E7-12:OPr was essential for optimal upwind flight and source contact. The two monoenes, Z5-12:OAc and Z5-12:OH, alone or binary mixtures, had no effect on behavioral responses when added to the optimal three-component blend.Conclusions/SignificanceThe fact that deviations from the optimal ratio of 100∶100∶4.5 of Z5,E7-12:OAc, Z5,EZ7-12:OH, and Z5,E7-12:OPr resulted in marked decreases in male responses suggests that biosynthesis of the pheromone components is precisely controlled. The optimal blend of the sex pheromone components of D. tabulaeformis worked out in this study should find immediate use in monitoring this pest in Chinese forests.