18 results on '"Komatsu, Hikaru"'
Search Results
2. Changes in the sapwood area of Japanese cedar and cypress plantations after thinning
- Author
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Komatsu, Hikaru and Kume, Tomonori
- Published
- 2015
- Full Text
- View/download PDF
3. 樹液流計測と切り木実験により推定したQuercus serrataの蒸散量の比較
- Author
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Chiu, Chen-Wei, Tateishi, Makiko, Komatsu, Hikaru, and Otsuki, Kyoichi
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Quercus ,蒸散 ,cutting-tree experiment ,sap flux ,環孔材 ,切り木実験 ,ring-porous ,コナラ ,calibration ,樹液流 ,transpiration ,キャリブレーション - Abstract
Although the sap-flux method has been widely used to estimate tree transpiration, the accuracy of the estimates has not been sufficiently examined, especially for ring-porous species. Quercus serrata is a ring-porous species that is widely distributed in warm-temperate forests in East Asia, including Japan. We compared the tree transpiration estimated by the sap-flux method using Granier sensors and by a cutting-tree experiment to evaluate the applicability of the sap-flux method to this species. The transpiration estimated by the sap-flux method correlated well (r = 0.985, p < 0.05) with that measured in the cutting-tree experiment, indicating that the sap-flux method succeeded in detecting diurnal changes in transpiration. However, the slope of the regression line was 1.84, indicating that transpiration was underestimated by the sap-flux method. These results suggest that Granier sensors can be used to estimate transpiration in Q. serrata but that calibration is necessary., 樹液流計測は樹木蒸散を推定するために広く用いられているが、環孔材樹種で用いる際の推定精度に関しては十分に検討されていない。コナラ(Quercus serrata)は日本を含む東アジアの温帯林に広く分布する環孔材樹種である。本研究では、樹液流計測(グラニエ法)で推定した樹液流量と切り木実験により得られた吸水量を比較することで、コナラへの樹液流計測の適用可能性を評価した。樹液流量は切り木実験による吸水量と高い相関を示し(r=0.985, p
- Published
- 2014
4. Relationship Between Tree Height and Transpiration for Individual Japanese Cypress (Chamaecyparis Obtusa)
- Author
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Kume Tomonori, Otsuki Kyoichi, Komatsu Hikaru, Higashi Naoko, Tsuruta Kenji, and Kumagai Tomo'omi
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Tree (data structure) ,biology ,Chamaecyparis ,Environmental science ,Forestry ,biology.organism_classification ,Cypress ,Transpiration - Published
- 2008
5. 林内の気温鉛直分布が蒸散・光合成に与える影響
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Komatsu, Hikaru, Kumagai, Tomo'omi, and Hotta, Norifumi
- Subjects
air temperature ,forest canopy ,蒸散 ,photosynthesis ,樹冠 ,多層モデル ,光合成 ,multilayer canopy models ,vertical distribution ,気温 ,鉛直分布 ,transpiration - Abstract
This study examined whether accurately simulating vertical air temperature (AT) distribution within forest canopies is essential for predicting vertical photosynthesis and transpiration distribution using multilayer canopy models. Inspecting earlier observational studies that reported vertical AT distribution within forest canopies, we showed that the common vertical AT difference within forest canopies was lower than 3.0℃. We showed, using a leaf-scale transpiration-photosynthesis model, that a 3.0℃ AT difference caused smaller differences in leaf- scale photosynthesis and transpiration rates than a common vertical difference in photosynthetic active radiation (PAR) intensity within forest canopies when AT was higher than ca. 15℃. While, the AT difference caused larger differences in leaf-scale photosynthetic and transpiration rates than the PAR difference when AT was lower than ca. 10℃. However, the ranges in the rates with changing AT by 3.0℃ were comparable with predictability of a leaf-scale transpiration-photosynthesis model. Thus, we conclude that accurately simulating AT distribution is not essential at this stage for calculating vertical photosynthesis and transpiration distribution using multilayer canopy models., 本研究では、林内気温鉛直分布を正確に再現することが、林内光合成・蒸散鉛直分布を多層モデルで推定するのに不可欠かどうかを調べた。筆者らは既存文献を踏査して、林内で計測される鉛直方向の気温差が通常3.0℃以下であることを示した。つづいて、単葉スケールの蒸散・光合成モデルによる計算によってつぎのことを示した。気温が約15℃以上のとき、3.0℃の気温の差が引き起こす光合成・蒸散量の違いは、林内で通常計測される光合成有効放射量の鉛直方向の差が引き起こす光合成・蒸散量の違いよりも小さい。一方、気温が約10℃以下のとき、3.0℃の気温の差が引き起こす光合成・蒸散量の違いは、林内で通常計測される光合成有効放射量の鉛直方向の差が引き起こす光合成・蒸散量の違いよりも大きいが3.0℃の気温の差が引き起こす光合成・蒸散量の違いは、単葉スケールの蒸散・光合成モデルの予測精度と同程度である。したがって、現時点において、林内気温鉛直分布を正確に再現することは、林内光合成・蒸散鉛直分布を多層モデルで推定するのに不可欠ではないと結論した。
- Published
- 2007
6. 九州のマテバシイ林で計測された土壌水分減少による樹液流速の低下
- Author
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Komatsu, Hikaru, Katayama, Ayumi, Kume, Tomonori, and Otsuki, Kyoichi
- Subjects
森林 ,forest canopy ,蒸散 ,sap flow ,土壌水分減少 ,Lithocarpus edulis ,soil water deficit ,マテバシイ ,transpiration ,樹液流 - Abstract
This paper examines transpiration reduction due to soil water deficits observed in a Lithocarpus edulis forest on Kyushu Island, south-western Japan. Continuous sap flow measurements were performed on six trees to monitor changes in tree transpiration rates. A reduction in sap flow velocity was observed in the period between late-September and late-October 2003. Precipitation amounts for this period were limited resulting in a corresponding low soil matric potential. A clear reduction in sap flow velocity occurred when soil matric potential at a 10 cm depth was < - 70 ( kPa) . Sap flow velocity scaled for 1. 0 kPa vapor pressure deficit declined by 42 % when soil matric potential at a 10 cm depth was < - 70 (kPa) compared to ≥ - 70 ( kPa) . In addition, intensive leaf-scale physiological measurements were performed on two days that had contrasting soil matric potentials. The intensive measurements showed lower leaf transpiration rates and stomatal conductance on the day with the lower soil matric potential. This finding suggests soil water deficits caused stomatal closure and therefore reduction in tree transpiration. Sap flow velocity and leaf water potential data showed that stem hydraulic conductance did not decline with low soil matric potential when compared to the day with higher soil matric potential., 本論は,九州のマテバシイ林で計測された土壌水分減少による蒸散低下を調べたものである。蒸散の変化を観測するために森林内の6本の樹木において樹液流計測を行ったところ,2003年9月下旬から10月下旬にかけて樹液流速の低下が認められた。この期間は降水量が少なかったために,土壌マトリックポテンシャルが低下していた。樹液流速の低下は,深度10 cmの土壌マトリックポテンシャルが-70 kPa以下のときに顕著であった。大気飽差が1.0 kPaのときの樹液流速は,土壌マトリックポテンシャルが-70 kPa以下のとき,土壌マトリックポテンシャルが-70 kPa以上のときに比べて42%低下していた。樹液流計測に加えて単葉スケールでの樹木生理計測を,土壌マトリックポテンシャルの異なる2日を選んで行った。その結果,単葉の蒸散量と気孔コンダクタンスは,土壌マトリックポテンシャルが低い日において小さかった。このことは,土壌水分減少が気孔の閉鎖を引き起こし,その結果,樹木の蒸散が低下したことを示唆している。樹液流速と水ポテンシャルの関係から,土壌マトリックポテンシャルの低下による幹の通水コンダクタンスの低下は認められなかった。
- Published
- 2007
7. スギ人工林の冬季の蒸散 : 通年樹液流計測に基づく解析
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KOMATSU, Hikaru, KUME, Tomonori, YOSHIFUJI, Natsuko, HOTTA, Norifumi, and SUZUKI, Masakazu
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蒸散 ,Evergreen ,Cryptomeria japonica plantation ,常緑 ,Sap flow ,Winter ,スギ人工林 ,Transpiration ,樹液流 ,冬季 - Published
- 2007
8. Differences in sap flux-based stand transpiration between upper and lower slope positions in a Japanese cypress plantation watershed.
- Author
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Kume, Tomonori, Tsuruta, Kenji, Komatsu, Hikaru, Shinohara, Yoshinori, Katayama, Ayumi, Ide, Jun'ichiro, and Otsuki, Kyoichi
- Subjects
PLANT transpiration ,CYPRESS ,CHAMAECYPARIS obtusa ,WATERSHEDS ,EVAPOTRANSPIRATION - Abstract
This study investigated the difference in stand transpiration ( E) between upper (UP) and lower (LP) slope plots of a Japanese cypress ( Chamaecyparis obtusa) watershed to obtain catchment-scale E estimates. Sap flux-based stand-scale E estimates were conducted on the UP and LP, which had contrasting stand structures (diameter at breast height and tree height) despite being the same age. The plant area index was similar in the UP and LP, while the total sapwood area ( A
S_stand ) and the mean sap flux density ( JS ) in the UP were 23% and ~30% lower, respectively, than those of the LP. Stand-scale E is the product of the AS_stand and JS in a stand. As a result, E in the UP was ~50% lower than that in the LP. This ratio was relatively constant throughout the year, which was supported by a similar decline in E, which resulted from soil water decline in the UP and LP. Canopy conductance ( GC ) in the UP was ~50% smaller than that of the LP. In contrast to previous studies that showed a consistent JS along a slope, the differences in E between the UP and LP were caused by differences in AS_stand and JS , probably because the UP exhibited a lower GC per unit leaf area than the LP. Additionally, evapotranspiration ( ET), the sum of sap flux-scaled E plus rainfall interception, was 8-14% lower than the catchment water balance ET (precipitation minus runoff), which suggests the feasibility of calculating sap flux-scaled E for the two slope positions. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]- Published
- 2016
- Full Text
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9. A model relating transpiration for Japanese cedar and cypress plantations with stand structure.
- Author
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Komatsu, Hikaru, Shinohara, Yoshinori, Kumagai, Tomo’omi, Kume, Tomonori, Tsuruta, Kenji, Xiang, Yang, Ichihashi, Ryuji, Tateishi, Makiko, Shimizu, Takanori, Miyazawa, Yoshiyuki, Nogata, Mari, Laplace, Sophie, Han, Tseng, Chiu, Chen-Wei, Ogura, Akira, Saito, Takami, and Otsuki, Kyoichi
- Subjects
CRYPTOMERIA japonica ,CYPRESS ,PLANTATIONS ,FOREST management ,WATER balance (Hydrology) ,FOREST canopies - Abstract
Previous studies have revealed that changes in forest structure due to management (e.g., thinning, aging, and clearcutting) could affect the forest water balance. However, there are unexplained variability in changes in the annual water balance with changing structure among different sites. This is the case even when analyzing data for specific species/regions. For a more advanced and process-based understanding of changes in the water balance with changing forest structure, we examined transpiration ( E ) observed using the sap-flux method for 14 Japanese cedar and cypress plantations with various structure (e.g., stem density and diameter) in Japan and surrounding areas and developed a model relating E with structural parameters. We expressed E using the simplified Penman–Monteith equation and modeled canopy conductance ( G c ) as a product of reference G c ( G cref ) when vapor pressure deficit is 1.0 kPa and functions expressing the responses of G c to meteorological factors. We determined G cref and parameters of the functions for the sites separately. E observed for the 14 sites was not reproduced well by the model when using mean values of G cref and the parameters among the sites. However, E observed for the sites was reproduced well when using G cref determined for each site and mean values of the parameters of the functions among the sites, similar to the case when using G cref and the parameters of the functions determined for each site. These results suggest that considering variations in G cref among the sites was important to reproduce variations in E , but considering variations in the parameters of the functions was not. Our analysis revealed that G cref linearly related with the sapwood area on a stand scale ( A ) and that A linearly related with stem density ( N ) and powers of the mean stem diameter ( d m ). Thus, we proposed a model relating E with A (or N and d m ), where G cref was calculated from A (or N and d m ) and the parameters of the functions were assumed to be the mean values among the sites. This model estimates changes in E with changing structure from commonly available data ( N and d m ), and therefore helps improve our understanding of the underlying processes of the changes in the water balance for Japanese cedar and cypress plantations. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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10. Canopy conductance for a Moso bamboo (Phyllostachys pubescens) forest in western Japan
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Komatsu, Hikaru, Onozawa, Yuka, Kume, Tomonori, Tsuruta, Kenji, Shinohara, Yoshinori, and Otsuki, Kyoichi
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FOREST canopies , *PHYLLOSTACHYS pubescens , *TAIGAS , *WATER balance (Hydrology) , *CARBON cycle , *PHOTOSYNTHESIS , *PLANT transpiration , *BAMBOO - Abstract
Abstract: In western Japan, Moso bamboo (Phyllostachys pubescens) forests have been expanding by replacing surrounding forests (e.g., coniferous plantation forests), which raises concerns about possible changes in terrestrial water and carbon cycles. Canopy conductance (G c ) is a critical parameter for determining canopy transpiration and photosynthesis. To clarify the characteristics of G c for Moso bamboo forests, we calculated G c during a growing season for a Moso bamboo forest on the basis of canopy transpiration measurements made using the sap-flux method, and then compared the G c value with values for coniferous plantation forests in western Japan. G c was primarily related to the vapor pressure deficit and secondarily to solar radiation, similar to the results obtained for other temperate forests. Under light-saturated conditions, G c for the bamboo forest was approximately twice that for the coniferous plantation forests despite the lower leaf area index for the bamboo forest. This implies higher canopy transpiration and photosynthesis for the bamboo forest, and therefore possible changes in terrestrial water and carbon cycles due to the replacement of coniferous plantation forests by bamboo forests. [Copyright &y& Elsevier]
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- 2012
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11. Stand-scale transpiration estimates in a Moso bamboo forest: II. Comparison with coniferous forests.
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Komatsu, Hikaru, Onozawa, Yuka, Kume, Tomonori, Tsuruta, Kenji, Kumagai, Tomo’omi, Shinohara, Yoshinori, and Otsuki, Kyoichi
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PLANT transpiration ,BAMBOO ,FOREST ecology ,COMPARATIVE studies ,FORESTS & forestry ,PHYLLOSTACHYS pubescens ,VAPOR pressure ,EVAPORATION (Meteorology) - Abstract
Abstract: In western Japan, Moso bamboo (Phyllostachys pubescens) forests have been expanding by replacing surrounding vegetation such as coniferous plantation forests and natural broadleaved forests. It has been speculated that the replacement of surrounding vegetation by bamboo forests could alter the vegetation water cycle and available water resources. We quantified stand-scale transpiration (E) in a bamboo forest on the basis of sap-flux measurements and compared the E value with values for coniferous forests. The annual E was estimated to be 567mm. Seasonal trends in E primarily corresponded to seasonal trends in the vapor pressure deficit. Annual E for the bamboo forest was higher than that for the coniferous forests by 12% of annual precipitation (P). This difference in annual E is comparable with the difference in annual interception evaporation (I) relative to P between bamboo and coniferous forests; previous studies reported lower I for bamboo forests by ∼10% of P. Thus, the sum of E and I was comparable for bamboo and coniferous forests. As this study is the first measuring E of bamboo forests, further studies are required to examine the generality of our results. [Copyright &y& Elsevier]
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- 2010
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12. Less than 20-min time lags between transpiration and stem sap flow in emergent trees in a Bornean tropical rainforest
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Kume, Tomonori, Komatsu, Hikaru, Kuraji, Koichiro, and Suzuki, Masakazu
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PLANT transpiration , *FORESTS & forestry , *STATISTICAL correlation , *BIOTIC communities - Abstract
Abstract: Sap flow velocities in stems (Sfs) were measured in four 50-m tall emergent trees in a Bornean tropical rainforest. Cross-correlation analysis was used to estimate time lags between diurnal patterns of Sfs and canopy-scale transpiration (Tr) calculated from a big-leaf model validated by water-vapor flux measurements at this site. The time lags between Sfs and Tr were found to be less than 20min in these trees in both wet and medium dry conditions. In addition, the time lags between Sfs and sap flow velocities measured in a branch at the top of an emergent tree were also less than 20min. These results are in contrast to those of previous studies conducted in a neo-tropical forest ecosystem, which reported significant time lags of 40–120min between transpiration and stem sap flow in emergent trees. The results of this study suggest that hydraulic resistance along the conductive pathway and internal water storage between tree crown and stem are insignificant for this forest. Our results also suggest that sap flow measurements conducted at accessible points can be used to estimate canopy transpiration on a diurnal time scale without accounting for the time lags between canopy transpiration and stem sap flows, despite the 50-m tall forest canopy at our site. [Copyright &y& Elsevier]
- Published
- 2008
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13. Reduction in soil water availability and tree transpiration in a forest with pedestrian trampling
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Komatsu, Hikaru, Katayama, Ayumi, Hirose, Shigeki, Kume, Atsushi, Higashi, Naoko, Ogawa, Shigeru, and Otsuki, Kyoichi
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METEOROLOGY , *EARTH sciences , *PHYSICAL sciences , *GEOLOGY - Abstract
Abstract: Many studies have reported tree growth reduction in forests with pedestrian trampling, implying a reduction of tree transpiration in such forests. We undertook observations of tree transpiration based on the heat-pulse method in a forest (Lithocarpus edulis) with pedestrian trampling. We prepared trampled and control plots in the forest. Tree transpiration in the trampled plot was reduced compared to that in the control plot after precipitation with a small-precipitation period preceding this. No difference was observed between plots in the small-precipitation period itself; during which tree transpiration was limited in both plots. After the period, tree transpiration recovery was not as complete in the trampled plot as in the control plot. This was caused by incomplete soil matric potential recovery at 20 cm and deeper in the trampled plot due to a lower infiltration rate. We believe this study is the first to report reduction of tree transpiration in a forest with pedestrian trampling. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
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14. Transpiration from a Cryptomeria japonica plantation, part 1: aerodynamic control of transpiration.
- Author
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Komatsu, Hikaru, Yihuei Kang, Kume, Tomonori, Yoshifuji, Natsuko, and Hotta, Norifumi
- Subjects
CRYPTOMERIA japonica ,CRYPTOMERIA ,PLANT canopies ,AERODYNAMICS ,PLANT transpiration ,VAPOR pressure ,NUMERICAL solutions to equations ,PLANT physiology - Abstract
To our knowledge, no one has examined the canopy conductance of a Cryptomeria japonica plantation, although such forests are very common in Japan. We plan to examine the canopy conductance of a Cryptomeria japonica plantation (canopy height 8 m) based on 1-year sap-flow data using the simplified Penman-Monteith equation. This study examines the effect of the aerodynamic control of transpiration before calculating canopy conductance using the simplified Penman-Monteith equation, because the equation assumes that the effect of aerodynamic control is negligible. To examine the effect of aerodynamic control, we examined the dependency of the relationship between the vapour pressure deficit (VPD) and transpiration on wind speed, when solar radiation, air temperature, and soil water content do not limit transpiration greatly. The relationship between VPD and the heat pulse velocity measured 11 m above the ground was dependent on wind speed only when the wind speed was < 0.7 m s
-1 . This suggests that the effect of aerodynamic control was negligible when the wind speed was < 0.7 m s-1 , but that the effect was not negligible when the wind speed was < 0.7 m s-1 . Therefore, we should use data from when the wind speed was ≥ 0.7 m s-1 for calculating canopy conductance Gc , based on the simplified Penman-Monteith equation. Although this criterion is site specific, the methods used to develop it are applicable to other sites. [ABSTRACT FROM AUTHOR]- Published
- 2006
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15. Transpiration from a Cryptomeria japonica plantation, part 2: responses of canopy conductance to meteorological factors.
- Author
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Komatsu, Hikaru, Yihuei Kang, Kume, Tomonori, Yoshifuji, Natsuko, and Hotta, Norifumi
- Subjects
CRYPTOMERIA japonica ,CRYPTOMERIA ,PLANT canopies ,VAPOR pressure ,UPPER air temperature ,SOLAR radiation ,NUMERICAL solutions to equations ,HYDROLOGIC models ,MODELS & modelmaking - Abstract
To our knowledge, there is no information on the canopy conductance of Cryptomeria japonica plantations, although such forests are very common in Japan. We examined the canopy conductance G
c of a C. japonica plantation based on 1-year sap-flow data using the simplified Penman-Monteith equation. After selecting data based on the criterion proposed in part 1 of this study (Komatsu et al., 2006. Hydrological Processes 20: this issue), we now examine Gc responses to meteorological factors. Gc was expressed using functions of solar radiation S (W m-2 ), the vapour pressure deficit D (kPa), and air temperature T (°C). The resulting functions were f1 (S) = [(1000 + 30)S]/[1000(S + 30)], f2 (D) = exp(-0.54D)/exp(-0.54), and f3 (T) = {[(30 - 5) + 14](T - 5)}/{(30 - 5)[(T - 5) + 14]), where f1 (S), f2 (D), and f3 (T) are functions expressing the Gc responses to S, D, and T respectively. The functions were characterized by comparing general functions for coniferous forests, which showed that it was necessary to consider f3 (T) to reproduce the 1-year transpiration at the site, and that f1 (S) and f2 (D) determined here were not very different from the general functions. This paper is the first to determine Gc responses to meteorological factors for a C. japonica plantation. When predicting transpiration from a C. japonica plantation using hydrological or ecological models, the functions determined here should be used instead of the default functions of the models. [ABSTRACT FROM AUTHOR]- Published
- 2006
- Full Text
- View/download PDF
16. Modeling evapotranspiration changes with managing Japanese cedar and cypress plantations.
- Author
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Komatsu, Hikaru
- Subjects
CRYPTOMERIA japonica ,FOREST management ,CYPRESS ,FOREST resilience ,PLANTATIONS - Abstract
• We developed a model tool to assist forest and water-resource policymaking. • The model focuses on two major plantation species in Japan. • The model can compare available water resources for different management scenarios. • The model can assess effectiveness of existing policy recommendations. • The study inspires development of similar models for other species/regions. Examining changes in evapotranspiration with forest management is one starting point for comprehensively understanding the impacts of forest management on water resources and forest resilience. This study builds on our previous work and develops a practical model that predicts changes in evapotranspiration with the management of Japanese cedar and cypress plantations. The model has distinct features that it requires only stem density, mean diameter at breast height, and basic meteorological data as inputs. This study first confirms that the model predicts annual evapotranspiration for cedar and cypress with relatively small errors (approximately 60 mm at the maximum). Next, this study shows that the model predicts changes in annual evapotranspiration with thinning and clearcutting of cedar and cypress with small errors (the mean absolute error of 86 mm). This study then demonstrates that coupling the model and yield tables enables prediction of annual evapotranspiration for different management scenarios and then the assessment of policy recommendations. Indeed, our model prediction suggests that the decrease in annual evapotranspiration with cedar and cypress aging is seemingly much smaller than that assumed in existing policy recommendations. Our model also suggests that the decrease in annual evapotranspiration with aging can more than triple by thinning at a rate of 50%, although this suggestion should be tested by future observation studies. The model is applicable only to Japanese cedar and cypress plantations under Japan's meteorological conditions, but similar models for other mono-specific plantations can be developed. This study will thus inspire forest scientists to develop models that assist policymaking for other species in other areas. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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17. Relationship between stem diameter and transpiration for Japanese cypress trees: Implications for estimating canopy transpiration.
- Author
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Tsuruta, Kenji, Komatsu, Hikaru, Kume, Tomonori, Otsuki, Kyoichi, Kosugi, Yoshiko, and Kosugi, Ken'ichiro
- Subjects
CYPRESS ,SPATIAL variation ,ACTINIC flux ,FOREST management ,DIAMETER ,TREES - Abstract
Previous studies reported relationships between stem diameter at breast height (DBH) and whole‐tree transpiration (Qt) across a variety of species and locations. It might be possible to develop a relationship between DBH and Qt with smaller variations when we focused on a single species. We attempted to develop such a relationship for Japanese cypress (Chamaecyparis obtusa), which is one of the major plantation species in Japan. We collated Qt for 51 Japanese cypress trees from nine different‐sized and different‐aged stands using the sap flux method. We found a strong linear correlation between DBH and the reference value of Qt at a vapour pressure deficit of 1 kPa (R = .883). This was a consequence of a strong correlation between DBH and sapwood area (AS_tree; R = .973) and the absence of a correlation between DBH and sap flux density (R = −.043). We confirmed that using the relationship between DBH and AS_tree, while assuming typical responses of sap flux density to meteorological factors, provides reasonable Qt estimates. This study also demonstrated how the DBH–Qt relationship can be applied to estimate changes in EC with changing forest management. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
18. Influences of canopy structure and physiological traits on flux partitioning between understory and overstory in an eastern Siberian boreal larch forest
- Author
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Xue, Bao-Lin, Kumagai, Tomo’omi, Iida, Shin’ichi, Nakai, Taro, Matsumoto, Kazuho, Komatsu, Hikaru, Otsuki, Kyoichi, and Ohta, Takeshi
- Subjects
- *
COMPARATIVE studies , *BIOENERGETICS , *CARBON dioxide , *HEATS of vaporization , *UNDERSTORY plants , *VACCINIUM vitis-idaea , *FOREST canopies , *TAIGA ecology - Abstract
Boreal forests play an important role in the global balance of energy and CO2. Our previous study of elaborate eddy covariance observations in a Siberian boreal larch forest, conducted both above the forest canopy and at the forest floor, revealed a significant contribution of latent heat flux (LE) from the cowberry understory to the whole ecosystem LE. Thus, in the present study, we examined what factors control the partitioning of whole ecosystem LE and CO2 flux into the understory and overstory vegetation, using detailed leaf-level physiology (for both understory and overstory vegetation) and soil respiration property measurements as well as a multilayer soil-vegetation-atmosphere transfer (SVAT) model. The modeling results showed that the larch overstory's leaf area index (LAI) and vertical profile of leaf photosynthetic capacity were major factors determining the flux partitioning in this boreal forest ecosystem. This is unlike other forest ecosystems that tend to have dense LAI. We concluded that control of the larch overstory's LAI had a relationship with both the coexistence of the larch with the cowberry understory and with the water resources available to the total forest ecosystem. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
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