Periodical Literature, 741 



Prolonged inundation of the forests along 



Flood the Rhine flood-plains in the summer of 



Injury 19 10 led to serious injury to many of the 



to trees, not only young plants, but old ones 



Forests. as well. Ashes, beeches, maples, cherry and, 



occasionally, black alder were diseased or 



dead at the base up to a height of about half a meter, while such 



trees as oak, elm, pine, aspen, willow and birch were practically 



uninjured. Trees on higher ground adjacent to the depressions 



to which the injury was confined were still sound, indicating that 



it was the duration of the flooding which caused the damage. 



At the diseased bases the bark was brown and dead, often 

 leaving strips, or "bridges," of living tissue. Only the surface 

 roots were killed and the larger ones only on the exposed upper 

 side. It is seen that the injured species are all relatively smooth- 

 barked. Tubeuf explains this selective action on the hypothesis 

 that the injury is due to asphyxiation of the inner bark tissues, 

 iftese inner tissues often being dead while the outer cortex was 

 still green. The water closely invests the smooth bark and 

 closes the lenticels, thus reducing respiratory activities to a mini- 

 mum. In the case of rough bark sufficient air is perhaps imprison- 

 ed in the crevices, or air-channels may even extend to the surface 

 of the water. The fact that stagnant water is much more in- 

 jurious than running water is strikingly confirmed. 



As to the disposition of the injured trees, Tubeuf suggests fell- 

 ing immediately all which have the roots killed, while those with 

 the bark dead entirely around the base can be left a year or more, 

 if necessary, before cutting. In case there is some living tissue left 

 it was thought the trees would survive. If the injury was too 

 severe, however, the bark would loosen and saprophytic fungi en- 

 ter, hence, it would be best to remove such trees, preferably in fall 

 or winter to avoid discoloration of the wood. Where the injured 

 area was small, say one-eighth to one-quarter of the circumfer- 

 ence, stripping away the dead bark and painting the wound with 

 carbolineum or ''raupenleim" should hasten the recovery. Young 

 trees, such as ash, will often send out sprouts below the injury 

 and may be cut back. 



Following the original discussion, the author reviews in some 

 detail earlier literature on the question of flood-injury. 



