北方土石山区典型树种耗水特征及环境影响因子
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摘要
研究北方土石山区植物耗水特征和环境影响因子对于构建稳定的植被生态系统具有重要意义,能够为当地植被恢复策略提供科学指导。在北京林业大学西山试验林场于2016年7月至10月利用热扩散探针的方法,结合同步观测的土壤含水率和气象因子,对刺槐和油松人工混交林进行蒸腾观测和分析。结果表明:(1)尽管刺槐和油松蒸腾的日变化规律相近,但二者蒸腾的季节变化规律不同;(2)两个树种蒸腾与VPD(饱和水汽压差)成顺时针时滞。刺槐蒸腾与太阳辐射成顺时针时滞,油松则成逆时针时滞;(3)二者与大气环境的耦合程度均较高(Ω<0.1),其气孔活动能够有效地控制蒸腾;(4)影响植物蒸腾的主要环境因子为太阳辐射(P<0.01)、VPD(P<0.01)和风速(P<0.01),其中由VPD引起的蒸腾量高于太阳辐射;(5)浅层土壤(0—50cm)的水分条件可能并不是影响植物蒸腾的重要因素。研究表明,在实际管理中可以采取调控气孔导度的手段来减少刺槐和油松人工林的耗水量,来降低水分这一人工林成活的限制因子,从而提高造林成活率。
Knowledge on the transpiration and environmental factors of forests facilitates the management of self-sustainable vegetation ecosystems in northern rocky mountainous areas,and provides scientific vegetation construction strategies. We surveyed forest transpiration and environmental factors in a mixed stand of Robinia pseudoacacia and Pinus tabulaeformis from July 11 to October 31,2016 in the experimental forest of the Beijing Forestry University,West Mountain. A thermal dissipation probe( TDP) system was applied to monitor the transpiration. To study the effects of the environmental factors on transpiration,volumetric soil water content,and meteorological variables were also monitored simultaneously,including solar radiation( R_n),air temperature( T),relative humidity( RH),wind speed( W),and precipitation( P). This study aimed to( 1) analyze forest transpiration processes and the transpiration responses to environmental factors,and( 2)determine the canopy coupling of the forest and quantify the contribution of different factors to transpiration. Results showed that( 1) the two species exhibited different seasonal transpiration trends despite their similar diurnal patterns. Thetranspiration of R. pseudoacacia decreased in autumn. By contrast,the transpiration of P. tabulaeformis was maintained throughout the growing season. The two species demonstrated similar transpiration patterns,but the transpiration of P.tabulaeformis was higher than that of R. pseudoacacia;( 2) Both species demonstrated hysteresis between transpiration and R_n. But R. pseudoacacia had a clockwise hysteresis loop,whereas P. tabulaeformis had an anti-clockwise loop. Hysteresis was also observed between transpiration and VPD( vapor pressure deficit). Both species showed clock-wise hysteresis loops with much higher transpiration rates in the morning than afternoon;( 3) The main environmental factors influencing transpiration included R_n( P < 0. 01),VPD( P < 0. 01),and W( P < 0. 01). Among them,VPD induced higher transpiration than R_n;( 4) the two species were well coupled to the ambient environment( Ω < 0.1); thus,their stomatal control over transpiration was efficient,and the effect of R_nwas highest before noon. The sap flow was observed to start earlier under high VPD conditions to avoid xylem cavitation or embolism owing to intense transpiration;( 5) The soil water condition of shallow layers( 0—50 cm) was not a major influencing factor on plant transpiration. Therefore,further study should include monitoring deeper soil layers to locate the soil water supply source. Based on our results,the transpiration of this mixed stand could be reduced through the abatement of canopy conductance. Thus,water restrictions would be alleviated and the survival rate would be increased. Both species could efficiently physiologically control transpiration.Therefore,in practice,the water consumption of this forest could be managed by reducing the canopy conductance. This could be carried out by pruning,or selecting a species with a low canopy conductance to increase the survival rate of the forest under limited water conditions.
Knowledge on the transpiration and environmental factors of forests facilitates the management of self-sustainable vegetation ecosystems in northern rocky mountainous areas,and provides scientific vegetation construction strategies. We surveyed forest transpiration and environmental factors in a mixed stand of Robinia pseudoacacia and Pinus tabulaeformis from July 11 to October 31,2016 in the experimental forest of the Beijing Forestry University,West Mountain. A thermal dissipation probe( TDP) system was applied to monitor the transpiration. To study the effects of the environmental factors on transpiration,volumetric soil water content,and meteorological variables were also monitored simultaneously,including solar radiation( R_n),air temperature( T),relative humidity( RH),wind speed( W),and precipitation( P). This study aimed to( 1) analyze forest transpiration processes and the transpiration responses to environmental factors,and( 2)determine the canopy coupling of the forest and quantify the contribution of different factors to transpiration. Results showed that( 1) the two species exhibited different seasonal transpiration trends despite their similar diurnal patterns. Thetranspiration of R. pseudoacacia decreased in autumn. By contrast,the transpiration of P. tabulaeformis was maintained throughout the growing season. The two species demonstrated similar transpiration patterns,but the transpiration of P.tabulaeformis was higher than that of R. pseudoacacia;( 2) Both species demonstrated hysteresis between transpiration and R_n. But R. pseudoacacia had a clockwise hysteresis loop,whereas P. tabulaeformis had an anti-clockwise loop. Hysteresis was also observed between transpiration and VPD( vapor pressure deficit). Both species showed clock-wise hysteresis loops with much higher transpiration rates in the morning than afternoon;( 3) The main environmental factors influencing transpiration included R_n( P < 0. 01),VPD( P < 0. 01),and W( P < 0. 01). Among them,VPD induced higher transpiration than R_n;( 4) the two species were well coupled to the ambient environment( Ω < 0.1); thus,their stomatal control over transpiration was efficient,and the effect of R_nwas highest before noon. The sap flow was observed to start earlier under high VPD conditions to avoid xylem cavitation or embolism owing to intense transpiration;( 5) The soil water condition of shallow layers( 0—50 cm) was not a major influencing factor on plant transpiration. Therefore,further study should include monitoring deeper soil layers to locate the soil water supply source. Based on our results,the transpiration of this mixed stand could be reduced through the abatement of canopy conductance. Thus,water restrictions would be alleviated and the survival rate would be increased. Both species could efficiently physiologically control transpiration.Therefore,in practice,the water consumption of this forest could be managed by reducing the canopy conductance. This could be carried out by pruning,or selecting a species with a low canopy conductance to increase the survival rate of the forest under limited water conditions.
引文
[1]张雷,孙鹏森,刘世荣.树干液流对环境变化响应研究进展.生态学报,2009,29(10):5600-5610.
[2]黄德卫,张德强,周国逸,刘世忠,Dennis O,李跃林.鼎湖山针阔叶混交林优势种树干液流特征及其与环境因子的关系.应用生态学报,2012,23(5):1159-1166.
[3]张涵丹,卫伟,陈利顶,于洋,杨磊,贾福岩.典型黄土区油松树干液流变化特征分析.环境科学,2015,36(1):349-356.
[4]刘鑫,张金池,庄家尧,顾哲衍,韩诚,吴雁雯.杉木幼树树干液流影响因子及其对杉木林蒸腾量的贡献.水土保持通报,2014,34(6):73-78.
[5]Wullschleger S D,Hanson P J.Sensitivity of canopy transpiration to altered precipitation in an upland oak forest:evidence from a long-term field manipulation study.Global Change Biology,2006,12(1):97-109.
[6]高冠龙,张小由,常宗强,鱼腾飞,赵虹.植物气孔导度的环境响应模拟及其尺度扩展.生态学报,2016,36(6):1491-1500.
[7]贾国栋,余新晓,朱建刚,樊登星.北京山区刺槐、栓皮栎生长旺季液流特性及影响因子.水土保持通报,2010,30(5):50-56.
[8]张璇,张会兰,王玉杰,王云琦,刘春霞,杨坪坪.缙云山典型树种树干液流径向变化及单株日蒸腾量估算.水土保持学报,2016,30(3):337-343.
[9]孙林,管伟,王彦辉,徐丽宏,熊伟.华北落叶松冠层平均气孔导度模拟及其对环境因子的响应.生态学杂志,2011,30(10):2122-2128.
[10]陈丽华,杨新兵,鲁绍伟,孙庆艳,肖洋,王宇.华北土石山区油松人工林耗水分配规律.北京林业大学学报,2008,30(S2):182-187.
[11]刘自强,余新晓,贾国栋,贾剑波,娄源海,张坤.北京山区侧柏和栓皮栎的水分利用特征.林业科学,2016,52(9):22-30.
[12]陈立欣,张志强,李湛东,张文娟,张晓放,董克宇,王国玉.大连4种城市绿化乔木树种夜间液流活动特征.植物生态学报,2010,34(5):535-546.
[13]Chen L X,Zhang Z Q,Li Z D,Tang J W,Caldwell P,Zhang W J.Biophysical control of whole tree transpiration under an urban environment in northern China.Journal of Hydrology,2011,402(3-4):388-400.
[14]邓文平,余新晓,贾国栋,李亚军,刘玉洁,白艳婧.利用稳定氢氧同位素定量区分栓皮栎旱季水分来源的方法比较.应用基础与工程科学学报,2013,21(3):412-422.
[15]Cˇermák J,Kucˇera J,Bauerle W L,Phillips N,Hinckley T M.Tree water storage and its diurnal dynamics related to sap flow and changes in stem volume in old-growth Douglas-fir trees.Tree Physiology,2007,27(2):181-198.
[16]梅婷婷,赵平,倪广艳,王权,曾小平,周翠鸣,蔡锡安,余孟好,曹庆平.树木胸径大小对树干液流变化格局的偏度和时滞效应.生态学报,2012,32(22):7018-7026.
[17]Kumagai T,Aoki S,Otsuki K,Utsumi Y.Impact of stem water storage on diurnal estimates of whole-tree transpiration and canopy conductance from sap flow measurements in Japanese cedar and Japanese cypress trees.Hydrological Processes,2009,23(16):2335-2344.
[18]赵晓伟,赵平,朱丽薇,倪广艳,曾小平,牛俊峰.木荷树干夜间水分补充的季节动态及其与树形特征和叶片生物量的关系.植物生态学报,2013,37(3):239-247.
[19]Murakami Y,Miki N H,Yang L,Zhang G,Wang L H,Yoshikawa K.Water transport properties of seven woody species from the semi-arid Mu Us Sandy Land,China.Landscape and Ecological Engineering,2016,12(2):209-220.
[20]O'Grady A P,Worledge D,Battaglia M.Constraints on transpiration of Eucalyptus globulus in southern Tasmania,Australia.Agricultural and Forest Meteorology,2008,148(3):453-465.
[21]Small E E,Mc Connell J R.Comparison of soil moisture and meteorological controls on pine and spruce transpiration.Ecohydrology,2008,1(3):205-214.
[22]陈立欣.树木/林分蒸腾环境响应及其生理控制[D].北京:北京林业大学,2013.
[23]司建华,冯起,张小由,常宗强,席海洋.热脉冲技术测定树干液流研究进展.冰川冻土,2007,29(3):475-481.
[24]韩路,王海珍,徐雅丽,牛建龙.灰胡杨蒸腾速率对气孔导度和水汽压差的响应.干旱区资源与环境,2016,30(8):193-197.
[25]倪广艳,赵平,朱丽薇,牛俊峰,赵秀华,曾小平.荷木整树蒸腾对干湿季土壤水分的水力响应.生态学报,2015,35(3):652-662.
[2]黄德卫,张德强,周国逸,刘世忠,Dennis O,李跃林.鼎湖山针阔叶混交林优势种树干液流特征及其与环境因子的关系.应用生态学报,2012,23(5):1159-1166.
[3]张涵丹,卫伟,陈利顶,于洋,杨磊,贾福岩.典型黄土区油松树干液流变化特征分析.环境科学,2015,36(1):349-356.
[4]刘鑫,张金池,庄家尧,顾哲衍,韩诚,吴雁雯.杉木幼树树干液流影响因子及其对杉木林蒸腾量的贡献.水土保持通报,2014,34(6):73-78.
[5]Wullschleger S D,Hanson P J.Sensitivity of canopy transpiration to altered precipitation in an upland oak forest:evidence from a long-term field manipulation study.Global Change Biology,2006,12(1):97-109.
[6]高冠龙,张小由,常宗强,鱼腾飞,赵虹.植物气孔导度的环境响应模拟及其尺度扩展.生态学报,2016,36(6):1491-1500.
[7]贾国栋,余新晓,朱建刚,樊登星.北京山区刺槐、栓皮栎生长旺季液流特性及影响因子.水土保持通报,2010,30(5):50-56.
[8]张璇,张会兰,王玉杰,王云琦,刘春霞,杨坪坪.缙云山典型树种树干液流径向变化及单株日蒸腾量估算.水土保持学报,2016,30(3):337-343.
[9]孙林,管伟,王彦辉,徐丽宏,熊伟.华北落叶松冠层平均气孔导度模拟及其对环境因子的响应.生态学杂志,2011,30(10):2122-2128.
[10]陈丽华,杨新兵,鲁绍伟,孙庆艳,肖洋,王宇.华北土石山区油松人工林耗水分配规律.北京林业大学学报,2008,30(S2):182-187.
[11]刘自强,余新晓,贾国栋,贾剑波,娄源海,张坤.北京山区侧柏和栓皮栎的水分利用特征.林业科学,2016,52(9):22-30.
[12]陈立欣,张志强,李湛东,张文娟,张晓放,董克宇,王国玉.大连4种城市绿化乔木树种夜间液流活动特征.植物生态学报,2010,34(5):535-546.
[13]Chen L X,Zhang Z Q,Li Z D,Tang J W,Caldwell P,Zhang W J.Biophysical control of whole tree transpiration under an urban environment in northern China.Journal of Hydrology,2011,402(3-4):388-400.
[14]邓文平,余新晓,贾国栋,李亚军,刘玉洁,白艳婧.利用稳定氢氧同位素定量区分栓皮栎旱季水分来源的方法比较.应用基础与工程科学学报,2013,21(3):412-422.
[15]Cˇermák J,Kucˇera J,Bauerle W L,Phillips N,Hinckley T M.Tree water storage and its diurnal dynamics related to sap flow and changes in stem volume in old-growth Douglas-fir trees.Tree Physiology,2007,27(2):181-198.
[16]梅婷婷,赵平,倪广艳,王权,曾小平,周翠鸣,蔡锡安,余孟好,曹庆平.树木胸径大小对树干液流变化格局的偏度和时滞效应.生态学报,2012,32(22):7018-7026.
[17]Kumagai T,Aoki S,Otsuki K,Utsumi Y.Impact of stem water storage on diurnal estimates of whole-tree transpiration and canopy conductance from sap flow measurements in Japanese cedar and Japanese cypress trees.Hydrological Processes,2009,23(16):2335-2344.
[18]赵晓伟,赵平,朱丽薇,倪广艳,曾小平,牛俊峰.木荷树干夜间水分补充的季节动态及其与树形特征和叶片生物量的关系.植物生态学报,2013,37(3):239-247.
[19]Murakami Y,Miki N H,Yang L,Zhang G,Wang L H,Yoshikawa K.Water transport properties of seven woody species from the semi-arid Mu Us Sandy Land,China.Landscape and Ecological Engineering,2016,12(2):209-220.
[20]O'Grady A P,Worledge D,Battaglia M.Constraints on transpiration of Eucalyptus globulus in southern Tasmania,Australia.Agricultural and Forest Meteorology,2008,148(3):453-465.
[21]Small E E,Mc Connell J R.Comparison of soil moisture and meteorological controls on pine and spruce transpiration.Ecohydrology,2008,1(3):205-214.
[22]陈立欣.树木/林分蒸腾环境响应及其生理控制[D].北京:北京林业大学,2013.
[23]司建华,冯起,张小由,常宗强,席海洋.热脉冲技术测定树干液流研究进展.冰川冻土,2007,29(3):475-481.
[24]韩路,王海珍,徐雅丽,牛建龙.灰胡杨蒸腾速率对气孔导度和水汽压差的响应.干旱区资源与环境,2016,30(8):193-197.
[25]倪广艳,赵平,朱丽薇,牛俊峰,赵秀华,曾小平.荷木整树蒸腾对干湿季土壤水分的水力响应.生态学报,2015,35(3):652-662.