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1.
Rapid micropropagation of Nepeta rtanjensis, N. sibirica and N. nervosa was performed. Qualitative and quantitative nepetalactone content in methanol extracts of in vitro grown plants was analysed by reverse-phase HPLC coupled with UV and MS detection. Only trans,cis-nepetalactone was detected in shoots of N. rtanjensis, while cis,trans-nepetalactone stereoisomer was present in N. sibirica. No nepetalactone was observed in shoots of N. nervosa. The antimicrobial activity of methanol extracts, against eight bacterial and eight fungal species, was evaluated. All the tested extracts showed significant antibacterial and strong antifungal activity. However, N. rtanjensis extract exhibited the best antimicrobial potential.  相似文献   

2.
Overexploitation of the African mahoganies, Khaya anthotheca and K. ivorensis, could lead to their commercial extinction in the near future. Efforts to establish plantations to sustain supply have been discouraged by the shoot borer Hypsipyla robusta Moore. We hypothesized that there is a shade level at which Hypsipyla attack and branching are reduced, but height growth is adequate. We report on the growth of these African mahoganies and Hypsipyla attack under three different forest canopy shade levels: open (55% open sky), medium shade (26% open), and deep shade (11% open). Hypsipyla attack on K. anthotheca was 85%, 11%, and 0% attack in the open, medium, and deep shade treatments, respectively. However, growth in medium and deep shade was slow. Mean tree height for K. anthotheca was 413.8, 126.2, and 54.5 cm in the open, medium and deep shade treatments, respectively. K. ivorensis showed similar trends. The reduced growth under these shade levels limit the use of this strategy for controlling Hypsipyla attack.  相似文献   

3.
We tested the effects of species and spacing of nurse trees on the growth of Hopea odorata, a dipterocarp tree indigenous to Southeast Asia, in a two-storied forest management system in northeast Thailand. Eucalyptus camaldulensis, Acacia auriculiformis, and Senna siamea were planted as nurse trees in 1987 at spacings of 4 m × 8 m, 2 m × 8 m, 4 m × 4 m, and 2 m × 4 m in the Sakaerat Silvicultural Research Station of the Royal Forest Department, Thailand. Seedlings of H. odorata were planted in the nurse tree stands at a uniform spacing of 4 m × 4 m and in control plots (no nurse trees) in 1990. Stem numbers of some nurse trees were thinned by half in 1994. The stem diameter and height of all trees were measured annually until 1995 and again in 2007. The mean annual increment (MAI) in volume was estimated as 8.2–10.1 m3 ha−1 year−1 for E. camaldulensis and 0.9–1.2 m3 ha−1 year−1 for S. siamea, smaller than reported elsewhere. This suggests that the site properties were not suitable for them. The MAI of A. auriculiformis was 7.9–9.8 m3 ha−1 year−1, within the reported range. Survival rates of H. odorata in the S. siamea stands and the control plots decreased rapidly during the first 2 years but then stayed constant from 1992. In contrast, survival rates of H. odorata in the E. camaldulensis and A. auriculiformis stands were initially high (>70%), but then decreased after 1995. Stem diameter, tree height, and stand basal area of H. odorata were large in both the S. siamea stands and the control plots from then. The growth of H. odorata was largest in the 2 m × 8 m S. siamea stands. In contrast, it was restricted in the E. camaldulensis and A. auriculiformis stands owing to strong shading by their canopies. Thinning by 50% tended to facilitate the growth of H. odorata temporarily in the E. camaldulensis and A. auriculiformis stands. The stand basal areas of nurse trees and of H. odorata showed a trade-off. These results suggest that the growth of H. odorata was maximized in the S. siamea stands. We assume, however, that the growth of H. odorata could be improved even in the E. camaldulensis and A. auriculiformis stands by frequent or heavy thinning.  相似文献   

4.
Six flavonol glycosides, compounds 1-3 from A. burnatii Gáyer and 4-6 from A. variegatum L., were obtained from their methanol extracts of aerial parts. The identified structures were quercetin 3-O-β-d-glucopyranoside-7-O-(6-E-p-coumaroyl)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (1), quercetin 3-O-β-d-glucopyranoside-7-O-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (2), quercetin 3-O-β-d-glucopyranoside-7-O-(6-E-caffeoyl)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (3), kaempferol 3-O-β-d-galactopyranoside-7-O-α-l-arabinopyranoside (4), quercetin 3-O-β-d-glucopyranoside (5), and kaempferol 3-O-β-d-glucopyranoside (6). Compounds 1, 2 and 4 were isolated for the first time. The antioxidant potential of the methanol extracts and pure compounds was tested with different assays.  相似文献   

5.
以“毛泡桐×白花泡桐”的优良无性系TF33和两个标准对照品种(白花泡桐C001与兰考泡桐C125)为试验材料,研究了泡桐优良无性系干材表型性状的杂种优势.结果表明:(1) TF33、C001、C125无性系间各性状存在广泛和显著的变异;(2)3个生长性状(接干高、接干材积和主干材积)与3个干形性状(通直度、接干形数和主干平均削度)为高度变异性状(CV≥30％),CV变幅为33.10％～53.19％;(3)接干因子是影响和决定性状杂种优势最终状况和总体表现的最重要因素;(4)通直度性状的遗传改良是毛泡桐×白花泡桐杂种无性系干形遗传改良的关键和瓶颈;(5)多数性状间存在极显著或显著的相关性,且不同的性状间相关性变化较大;(6) TF33较C001有显著的材积生长杂种优势,较C125没有显著杂种优势.  相似文献   

6.
Wound-healing plants from Traditional Chinese Medicine and described for wound healing in the Pharmacopoeia of People's Republic of China (2005 ed.) were investigated by in vitro bioassay on human skin cells. Therefore water and EtOH–water extracts (6:4, v/v) from 12 plants were tested on human primary dermal fibroblasts (pNHDF) and human HaCaT keratinocyte cell line by quantification of cell viability (MTT assay) and cellular proliferation (BrdU incorporation ELISA). No functional activity was found for extracts from Achyranthis bidentatae rhizoma, Cimicifugae rhizoma, Corydalis rhizoma, Gardeniae fructus, Houttuyniae herba, Lonicerae japonicae caulis, Paeoniae rubrae radix and Rehmanniae radix. Extracts from Notoginseng radix et rhizoma, Angelicae sinensis radix and Lonicerae japonicae flos showed moderate activity, while extracts from Moutan cortex (the root bark of Paeonia suffruticosa Andr., Ranunculaceae) increased cell viability of HaCaT keratinocytes and pNHDF in a dose-dependent manner significantly. Bioassay-guided fractionation yielded paeonol 1, the flavan-3-ols catechin 2 and epicatechin-3-O-gallate 3, the dimeric proanthocyanidin epicatechin-(4β → 8)-catechin 4, a mixture of trigalloyl-glucoses 5 and 1,2,3,4,6-penta-O-galloyl-β-d-glucose (PGG) 6. The proanthocyanidin-containing fractions as well as PGG-containing fractions contributed substantially to the stimulating effects. Especially PGG-containing fractions enhanced cell viability and cellular proliferation of HaCaT keratinocytes at concentration of 100 nM.From these data we conclude that indication claims for TCM herbal materials must be carefully investigated in order to establish evidence-driven use of such plants. In case of Moutan cortex skin cell stimulating effects have clearly been proven. These effects can be related to the polyphenol fractions of condensed and hydrolysable tannins.  相似文献   

7.
In regions of Australia of low–medium rainfall (500–800 mm/year), there is growing community and land-owner support for re-planting trees to achieve multiple environmental objectives, particularly amelioration of soil salinity. Sequestration of carbon by newly established trees is not only another important environmental benefit, but also a potential commercial benefit. To obtain estimates of carbon sequestered by species of commercial potential in such regions, we calibrated the carbon (C) accounting model FullCAM to Eucalyptus cladocalyx and Corymbia maculata plantations. This was achieved by harvesting trees of a range in sizes to determine the allometric relationships that most accurately predict biomass and stem density from measures of stem diameter. Predictions of stem diameter were obtained from a forest growth model (3-PG) previously calibrated for these two species. By applying these predictions of changes in stem diameter as the stand matures in our allometric relationships, we estimated changes in partitioning of biomass (between stem, branches, bark, foliage and roots) and stem wood density as the stand matures under scenarios of 500, 600 and 750 mm mean annual rainfall. We found that for both species, regardless of annual rainfall, throughout the rotation 37–50% of carbon sequestered in the total tree biomass was in the stem, 18–27% in both branches and roots, and the remainder in foliage or bark. However, rate of accumulation of carbon was dependent on annual rainfall, with average annual rate of sequestration of carbon in tree biomass and litter during the first rotation of E. cladocalyx (or C. maculata) increasing from 3.68 (or 4.17) to 4.72 (or 4.86) Mg C ha−1 yr−1 as annual rainfall increased from about 500 to 750 mm. Although it was predicted that decomposition negated any accumulation of debris between successive rotations, carbon was predicted to accumulate in sawlog products, given that assumed rates of product decomposition were slightly less than their rate of accumulation. This resulted in a slight increase (<8 Mg C ha−1) in predicted total sequestration of carbon between successive rotations.  相似文献   

8.
A new friedelane-type triterpene (1), along with seven known triterpenoids, was isolated from the stems and leaves of Calophyllum inophyllum Linn. Their structures were established as 3β, 23-epoxy-friedelan-28-oic acid (1), friedelin (2), epifriedelanol (3), canophyllal (4), canophyllol (5), canophyllic acid (6), 3-oxo-friedelan-28-oic acid (7), and oleanolic acid (8) by spectroscopic methods (NMR, EI-MS). The growth inhibitory effects of these triterpenoids on human leukemia HL-60 cells were determined.  相似文献   

9.
The effects of forest fertilization and Sirococcus shoot blight on growth of mature Norway spruce (Picea abies (L.) Karst.) were studied in a field experiment. The single tree fertilization experiment was established with 144 sample trees in the year 2000. These trees were selected among the dominant and co-dominant trees of the stand in a way that half of the trees exhibited symptoms of Sirococcus shoot blight and the other half did not. One-third of the sample trees were fertilized with dolomitic lime, one-third with kieserite and gypsum and one-third were left unfertilized as control. The treatments were randomly assigned to the sample trees. As the experimental design became unbalanced due to tree mortality caused by bark beetle infestation final analyses were performed with the volume growth data of 125 sample trees only. An analysis of covariance was used to evaluate the effect of fertilization and Sirococcus shoot blight on volume growth. The average volume increment of the period 1977–1980 was used as a covariate attribute, assuming that during this period growth was not yet affected by Sirococcus shoot blight. Indeed an effect of Sirococcus shoot blight on growth turned out to start after 1980 and the analysis revealed that over the whole period 1981–2006 trees with shoot blight symptoms had a significantly lower increment. The increment reduction of the nonfertilized trees by Sirococcus   was 7.46±2.907.46±2.90% in 1981 and was continuously increasing with time to 37±3.7837±3.78% by the year 2000. A significant positive effect of fertilization was only found for the kieserite+gypsumkieserite+gypsum variant from 2002 to 2006, with the highest surplus increment in 2004 with 31.6±15.231.6±15.2%, calculated as average over the diseased and healthy group. However, a mitigation of the Sirococcus-caused increment loss via fertilization with kieserite and gypsum was statistically significant only for the year 2003. A moderate relationship between basal area increment and disease severity was found, indicating decreasing basal area increment with increasing disease severity.  相似文献   

10.
Angiogenesis, the growth of new blood vessels from the pre-existing vasculature is of physiological and pathological importance. Substantial data over the last decade has implicated uncontrolled angiogenesis with various pathological states. Vascular endothelial growth factors (VEGFs) play a critical role in its regulation, and have become one of the most interesting anti-angiogenesis targets. We have investigated the anti-angiogenic potential of plant extracts in a preliminary ELISA screening. The n-BuOH extract obtained from the leaves of Monnina obtusifolia (Polygalaceae) demonstrated an inhibition of VEGF-A or Placental Growth Factor interaction with Flt-1 (VEGF receptor 1), with an inhibition over 50% in particular for VEGF-A/Flt-1 interaction at a concentration of 500 μg/mL. Successively fractionation of the bioactive n-BuOH extracts of M. obtusifolia aerial parts led to the isolation of six new compounds, 1-O-(4-hydroxy-2-methylene-butanoic acid)-6-O-β-d-(4-hydroxy-2-methylene-butanoyl)-glucopyranose (1), 1-O-(isopentenyl)-6-O-β-d-(4-hydroxy-2-methylene-butanoyl)-glucopyranose (2), 1-O-(4-hydroxy-2-methylene-butanoic acid)-6-O-β-d-(isovaleroyl)-glucopyranose (3), 1-O-(3-methylbut-3enyl)-6-O-β-d-(isovaleroyl)-glucopyranose (4), two new sucrose esters, 3,4-O-β-d-di-feruloyl-fructofuranosyl-6-O-α-d-(p-coumaroyl)-glucopyranoside (5), and 3,4-O-β-d-di-feruloyl-fructofuranosyl-6-O-α-d-(caffeoyl)-glucopyranoside (6), together with known flavonoids. Their structures were established on the basis of detailed spectral analysis. Since none of the isolated compounds showed a relevant inhibition of VEGFs, the biological activity observed for the butanolic extract might be due to the presence of a combination of compounds acting synergistically.  相似文献   

11.
濒危植物翠柏为柏科高大珍贵用材树种,通过对翠柏主要分布区墨江、昌宁翠柏植株树干解析,研究了两地翠柏的生长特性,结果表明:(1)翠柏在20年前生长缓慢,20—60年进入快速生长期,70年以后达到数量成熟,材积生长量开始下降并趋于稳定;(2)翠柏幼苗期具有耐荫性和长大后有喜光特性,墨江地区翠柏生长好于昌宁地区,其生长表现与两地自然条件相符合;(3)针对翠柏特点,提出幼苗时搭建荫棚,幼树时期进行疏伐,数量成熟时期进行间伐或疏伐等促进生长经营措施,为翠柏资源培育与保护奠定基础。  相似文献   

12.
Kim JE  Kim HJ  Pandit S  Chang KW  Jeon JG 《Fitoterapia》2011,82(3):352-356
Rheum undulatum root has been used traditionally in Korea for the treatment of dental diseases. The purpose of this study was to separate a fraction from R. undulatum showing anti-acid production activity against Streptococcus mutans biofilms and identify the main components in that fraction. Methanol extract of R. undulatum root and its fractions were prepared. To select a fraction exhibiting anti-acid production activity, suspension glycolytic pH-drop assay was performed. Among the fractions tested, dichloromethane fraction exhibited the strongest activity in a dose-dependent manner. To examine the effect of the selected fraction on the anti-acid production of S. mutans biofilms, 74 h old S. mutans biofilms were used. The selected fraction reduced the initial rate of acid production of S. mutans biofilms at sub-minimum inhibitory concentration (MIC) levels. HPLC qualitative analysis of the selected fraction indicated that the presence of anthraquinone derivatives, such as aloe-emodin, emodin, chrysophanol and physcion, as main components.  相似文献   

13.
Two new triterpene glycosides named ilexpublesnin A (1) and ilexpublesnin B (2) were isolated from the root of Ilex pubescens. Their structures were determined as 3-O-(β-d-xylopyranosyl)-28-O-(β-d-glucopyranosyl)-3β, 19α-dihydroxyurs-23-oxo-12-en-28-oic acid (1) and 28-O-(β-d-xylopyranosyl-(2 → 1)-β-d-glucopyranosyl)-3β, 19α-dihydroxyurs-23-oxo-12-en-28-oic acid (2) on the basis of chemical and spectroscopic methods.  相似文献   

14.
Bi L  Tian X  Dou F  Hong L  Tang H  Wang S 《Fitoterapia》2012,83(1):234-240
Four new oleanane type triterpenoid saponins (1-4) and a known saponin (5) were isolated from the root bark of Aralia taibaiensis Z.Z. Wang et H.C. Zheng. The structures of the four new compounds were elucidated as 3-O-{β-d-glucopyranosyl-(1 → 2)-[β-d-glucopyranosyl-(1 → 3)]-β-d-glucurono-pyranosyl}-olean-11,13(18)-diene-28-oic acid 28-O-β-d-glucopyranosyl ester (1), 3-O-{β-d-gluco-pyranosyl-(1 → 3)-[α-l-arabinofuranosyl-(1 → 4)]-β-d-glucuronopyranosyl}-olean-11,13(18)-diene-28-oic acid 28-O-β-D-glucopyranosyl ester (2), 3-O-{β-d-glucopyranosyl-(1 → 2)-[α-l-arabinofuranosyl-(1 → 4)]-β-d-glucuronopyranosyl}-oleanolic acid 28-O-β-D-glucopyranosyl ester (3) and 3-O-{β-d-glucopyranosyl-(1 → 2)-[β-d-glucopyranosyl-(1 → 3)]-β-d-glucuronopyranosyl}-oleanolic acid 28-O-β-d-glucopyranosyl ester (4), on the basis of extensive spectral analysis and chemical evidence. Compounds 1-5 exhibited moderate effects on antioxidant and antiglycation activities, which correlated with treatment of diabetes mellitus.  相似文献   

15.
Hemlock looper (Lambdina fiscellaria fiscellaria (Guen.)) is an economically damaging defoliator that undergoes periodic outbreaks in Newfoundland, Canada. It defoliates and causes extensive tree mortality to its primary host, balsam fir (Abies balsamea [L.] Mill.). We quantified tree survival using data from permanent sample plots (PSPs) and growth reduction or release using dendrochronology, and related these impacts to defoliation severity determined from annual aerial defoliation survey data. Such impact relationships are necessary as a fundamental input to a Decision Support System. Growth and survival of balsam fir, black spruce (Picea mariana (Mill.) B.S.P.) and white birch (Betula papyrifera Marsh.) were assessed from 1996 to 2008 in 48 Newfoundland Forest Service PSPs, selected based on four classes of defoliation severity. Two years of severe (71-100%) defoliation resulted in almost complete mortality for balsam fir, 10 years after defoliation, whereas survival was 70-80% for black spruce and white birch. Lower defoliation severity (1-2 years of moderate (31-70%) or 1 year of severe) resulted in approximately 60% survival for balsam fir and no reduction in survival for black spruce and white birch. Maximum growth reduction of balsam fir was 10-15% with 1 year of moderate-severe defoliation, 35-40% with 2 years of moderate defoliation, and about 50% with 2 years of severe defoliation. Growth recovered to pre-defoliation rates 5 years after defoliation ceased in all severity classes. Growth reduction and recovery of black spruce were more variable and lower than for balsam fir, and white birch exhibited only minor (<10%) growth reduction during the defoliation year or 1 year after defoliation. Control measures should focus on avoiding severe defoliation for two consecutive years.  相似文献   

16.
An understanding of growth and photosynthetic potential of subtropical rainforest species to variations in light environment can be useful for determining the sequence of species introductions in rainforest restoration projects and mixed species plantations. We examined the growth and physiology of six Australian subtropical rainforest tree species in a greenhouse consisting of three artificial light environments (10%, 30%, and 60% full sunlight). Morphological responses followed the typical sun-shade dichotomy, with early and late secondary species (Elaeocarpus grandis, Flindersia brayleyana, Flindersia schottiana, and Gmelina leichhardtii) displaying higher relative growth rate (RGR) compared to mature stage species (Cryptocarya erythroxylon and Heritiera trifoliolatum). Growth and photosynthetic performance of most species reached a maximum in 30–60% full sunlight. Physiological responses provided limited evidence of a distinct dichotomy between early and late successional species. E. grandis and F. brayleyana, provided a clear representation of early successional species, with marked increase in Amax in high light and an ability to down regulate photosynthetic machinery in low light conditions. The remaining species (F. schottiana, G. leichhardtii, and H. trifoliolatum) were better represented as falling along a shade-tolerant continuum, with limited ability to adjust physiologically to an increase or decrease in light, maintaining similar Amax across all light environments. Results show that most species belong to a shade-tolerant constituency, with an ability to grow and persist across a wide range of light environments. The species offer a wide range of potential planting scenarios and silvicultural options, with ample potential to achieve rapid canopy closure and rainforest restoration goals.  相似文献   

17.
Insect damage to production forests has the potential to reduce financial returns by retarding tree growth and causing mortality, however, long-term realised quantification of these losses is rare. In order to help elucidate economic damage thresholds for making spray decisions we capitalised on a natural outbreak of autumn gum moth, Mnesampela privata, in a 2-year-old Eucalyptus nitens plantation. Following the partial chemical control of this insect outbreak we measured the tree growth variables diameter at breast height over bark and height of five differing tree defoliation classes for 75 months following tree damage. At the end of this period a threshold model was fitted to describe the relationship between tree defoliation and realised tree wood volumes. The model revealed that realised stand wood volume was not significantly affected up until defoliation exceeded 60% and then declined sharply after this defoliation level was reached. Further support for this defoliation threshold was evident from multiple comparisons among defoliation classes that showed 50% defoliated trees did not have significantly different wood volume compared to more lightly defoliated trees, but did have significantly greater wood volume compared to trees that were 72% or more defoliated. To determine if the realised differences in wood volume resulted in differences in yield over a plantation rotation the E. nitens growth model NITGRO was used to on-grow trees to age 15 years for a ‘best case’ (type 1 growth response, constant growth rates from last inventory until harvest) and ‘worst case’ (type 2 growth response, divergent growth rates from last inventory until harvest) scenario. The threshold model was then fitted to the outcomes of both scenarios and the economic consequences of defoliation were clearly dependent on the growth function assumed.  相似文献   

18.
The antifungal effects of citral, eugenol, nerolidol and α-terpineol on Trichophyton mentagrophytes were investigated. Citral over 0.1 mg/ml strongly inhibited the hyphal growth of T. mentagrophytes, and the antifungal activity of α-terpineol was less effective. The morphological changes of the fungus exposed to the terpenes were observed by electron microscopy. The hyphae were distorted and collapsed at 0.2, 0.4 and 1 mg/ml of eugenol, nerolidol and α-terpineol respectively, and cell membrane and organelles were irreversibly damaged at 0.2 mg/ml citral.  相似文献   

19.
Wang F  Guan Y 《Fitoterapia》2012,83(1):13-17
Four new nor-dammarane triterpenoids, 12β-O-acetyl-15α,28-dihydoxy-17β-methoxy-3-oxo-20,21,22-23,24,25,26,27-octanordammanran (1), 12β-O-acetyl-15α,17β,28-trihydoxy-3-oxo-20,21,22-23,24,25,26,27-octanordammanran (2), 12β-O-acetyl-15α,28-dihydoxy-3-oxo-17-en-20,21,22-23,24,25,26,27-octanordammanran (3), and 12β,15α,17β,28-tetrahydoxy-3-oxo-20,21,22-23,24,25,26,27-octanordammanran (4), were isolated from the 70% EtOH extract of Dysoxylum hainanense. The structures of the new compounds were elucidated by spectral methods. All the triterpenoids were in vitro evaluated for their cytotoxic activities against four tumor cell lines (A549, SK-OV-3, SKMEL-2 and HCT15).  相似文献   

20.
There is limited understanding of the carbon (C) storage capacity and overall ecological structure of old-growth forests of western Montana, leaving little ability to evaluate the role of old-growth forests in regional C cycles and ecosystem level C storage capacity. To investigate the difference in C storage between equivalent stands of contrasting age classes and management histories, we surveyed paired old-growth and second growth western larch (Larix occidentalis Nutt)–Douglas-fir (Pseudostuga menziesii var. glauca) stands in northwestern Montana. The specific objectives of this study were to: (1) estimate ecosystem C of old-growth and second growth western larch stands; (2) compare C storage of paired old-growth–second growth stands; and (3) assess differences in ecosystem function and structure between the two age classes, specifically measuring C associated with mineral soil, forest floor, coarse woody debris (CWD), understory, and overstory, as well as overall structure of vegetation. Stands were surveyed using a modified USFS FIA protocol, focusing on ecological components related to soil, forest floor, and overstory C. All downed wood, forest floor, and soil samples were then analyzed for total C and total nitrogen (N). Total ecosystem C in the old-growth forests was significantly greater than that in second growth forests, storing over 3 times the C. Average total mineral soil C was not significantly different in second growth stands compared to old-growth stands; however, total C of the forest floor was significantly greater in old-growth (23.8 Mg ha−1) compared to second growth stands (4.9 Mg ha−1). Overstory and coarse root biomass held the greatest differences in ecosystem C between the two stand types (old-growth, second growth), with nearly 7 times more C in old-growth trees than trees found on second growth stands (144.2 Mg ha−1 vs. 23.8 Mg ha−1). Total CWD on old-growth stands accounted for almost 19 times more C than CWD found in second growth stands. Soil bulk density was also significantly higher on second growth stands some 30+ years after harvest, demonstrating long-term impacts of harvest on soil. Results suggest ecological components specific to old-growth western larch forests, such as coarse root biomass, large amounts of CWD, and a thick forest floor layer are important contributors to long-term C storage within these ecosystems. This, combined with functional implications of contrasts in C distribution and dynamics, suggest that old-growth western larch/Douglas-fir forests are both functionally and structurally distinctive from their second growth counterparts.  相似文献   

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