Water Use in Neighbouring Stands of Beech (Fagus Sylvatica L.) and Black Alder (Alnus Glutinosa (L.) Gaertn.). Herbst, M., Eschenbach, C., & Kappen, L. 56(2):107–120.
Water Use in Neighbouring Stands of Beech (Fagus Sylvatica L.) and Black Alder (Alnus Glutinosa (L.) Gaertn.) [link]Paper  doi  abstract   bibtex   
In neighbouring stands of beech and black alder in northern Germany, transpiration, soil evaporation and interception evaporation were estimated for four meteorologically different years. By means of standard weather data a two-layer evaporation model of the Shuttleworth-Wallace type was applied. In the 105-year-old beech forest (tree height 29 m, maximum leaf area index 4.5), annual transpiration (Tr) varied between 326 and 421 mm (mean 389 mm or 50 % of gross precipitation, PG) and annual evapotranspiration (ET) between 567 and 665 mm (mean 617 mm or 79 % of P G). In the 60-year-old alder stand (tree height 18 m, maximum leaf area index 4.8) the respective values were 375 and 658 mm (mean 538 mm or 69 % of PG) for Tr and 612 and 884 mm (mean 768 mm or 99 % of PG, for ET. In years with high radiation input, ET in the alder stand (along a lake shore with unlimited water availability) exceeded both PG and net radiation. The higher inter-annual, weather-dependent variation of transpiration in alder corresponds to a lower capacity of stomatal regulation in alder if compared with beech. [Excerpt] [...] The results of our study illustrate a difference between the strategies of water use of the two investigated tree species. Beech maintains a more constant water consumption than alder (see figures 4 and 5). Thus, it regulates its water use more strictly and is more 'conservative' with respect to amounts of evaporation, i.e. less weather-dependent. This can be observed during fine weather periods in summer when the combined action of stomatal regulation and root growth or sapwood storage (or both) ensures that not more than 5 mm water per day is consumed, but that this amount is kept constant even during rainless periods of several weeks. This contrasts with more drought-tolerant tree species like oak, which exhibits a strong stomatal response to decreasing soil water content and uses available water even more sparingly than beech. Alder, however, shows a much weaker regulation and exhibits no significant differences in transpiration behaviour between inner and outer parts of the crown or even between wet and dry sites. By shedding leaves alder avoids rather than tolerates drought if water becomes short. Our results indicate that alder trees growing with unlimited water availability have a strongly varying water consumption depending on leaf area index, radiation input and the evaporative demand of the atmosphere. The very high gcs values found in alder also cause Ω to be higher than in beech. Water turnover rates in alder stands are generally much higher than in beech stands as long as water availability is unlimited. [] The previously discussed differences in water use by the two species correspond to similar differences in the their carbon balance and may characterise why alder is a representative of early successional forest phases, whereas beech is a typical late successional species. [...]
@article{herbstWaterUseNeighbouring1999,
  title = {Water Use in Neighbouring Stands of Beech ({{Fagus}} Sylvatica {{L}}.) and Black Alder ({{Alnus}} Glutinosa ({{L}}.) {{Gaertn}}.)},
  author = {Herbst, Mathias and Eschenbach, Christiane and Kappen, Ludger},
  date = {1999},
  journaltitle = {Annals of Forest Science},
  volume = {56},
  pages = {107--120},
  issn = {0003-4312},
  doi = {10.1051/forest:19990203},
  url = {https://doi.org/10.1051/forest:19990203},
  abstract = {In neighbouring stands of beech and black alder in northern Germany, transpiration, soil evaporation and interception evaporation were estimated for four meteorologically different years. By means of standard weather data a two-layer evaporation model of the Shuttleworth-Wallace type was applied. In the 105-year-old beech forest (tree height 29 m, maximum leaf area index 4.5), annual transpiration (Tr) varied between 326 and 421 mm (mean 389 mm or 50 \% of gross precipitation, PG) and annual evapotranspiration (ET) between 567 and 665 mm (mean 617 mm or 79 \% of P G). In the 60-year-old alder stand (tree height 18 m, maximum leaf area index 4.8) the respective values were 375 and 658 mm (mean 538 mm or 69 \% of PG) for Tr and 612 and 884 mm (mean 768 mm or 99 \% of PG, for ET. In years with high radiation input, ET in the alder stand (along a lake shore with unlimited water availability) exceeded both PG and net radiation. The higher inter-annual, weather-dependent variation of transpiration in alder corresponds to a lower capacity of stomatal regulation in alder if compared with beech.

[Excerpt] [...] The results of our study illustrate a difference between the strategies of water use of the two investigated tree species. Beech maintains a more constant water consumption than alder (see figures 4 and 5). Thus, it regulates its water use more strictly and is more 'conservative' with respect to amounts of evaporation, i.e. less weather-dependent. This can be observed during fine weather periods in summer when the combined action of stomatal regulation and root growth or sapwood storage (or both) ensures that not more than 5 mm water per day is consumed, but that this amount is kept constant even during rainless periods of several weeks. This contrasts with more drought-tolerant tree species like oak, which exhibits a strong stomatal response to decreasing soil water content and uses available water even more sparingly than beech. Alder, however, shows a much weaker regulation and exhibits no significant differences in transpiration behaviour between inner and outer parts of the crown or even between wet and dry sites. By shedding leaves alder avoids rather than tolerates drought if water becomes short. Our results indicate that alder trees growing with unlimited water availability have a strongly varying water consumption depending on leaf area index, radiation input and the evaporative demand of the atmosphere. The very high gcs values found in alder also cause Ω to be higher than in beech. Water turnover rates in alder stands are generally much higher than in beech stands as long as water availability is unlimited.

[] The previously discussed differences in water use by the two species correspond to similar differences in the their carbon balance and may characterise why alder is a representative of early successional forest phases, whereas beech is a typical late successional species. [...]},
  keywords = {*imported-from-citeulike-INRMM,~INRMM-MiD:c-14147800,alnus-glutinosa,comparison,evapotranspiration,fagus-sylvatica,flooding-tolerance,forest-resources,solar-radiation,waterlogging},
  number = {2}
}
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