Eastern hemlock - Tsuga canadensis 


Cut out section:  

[Spaulding as early as 1914 gave a good account of the pathogenic and psychogenic disorders of eastern hemlock, as known at that time, much of which, except for nomenclature changes, is still valid (1999).  Eastern hemlock is subject to several leaf, shoot, and cone rusts; and many other fungi can attack foliage and twigs.  The species is seldom damaged by fungi after the seedling stage, but it can decline rapidly when suddenly exposed following cutting or clearing, and the wood tends to be "shaky ." 

Young hemlock is very sensitive to fire injury.   The tree's ultimate emergence as a major component in many stands is due less to resistance to impacts than to its great tolerance to shade, its capacity to thrive on a wide range of soils, and its resistance to ice damage.   Hemlock's limber branches droop with loads of ice or snow, and recover well later.. 

Hemlocks of saw log size are notoriously subject to wind-shake (481), to radial stress cracks, and, following sudden exposure, to sunscald1 of the bark, and to death.   These reactions may be the result of many adverse effects associated with a changed regime of solar heat and soil moisture and culminate in a decline often referred to as post-logging decadence2.   When hemlocks are left as residual trees following partial cutting, and when they are exposed, through road or other construction or clearing, they often die3, even when their root area is covered with understory brush.  Eastern hemlock is also considered to be one of the species most sensitive to sulfur fumes from smelters4.  (An interesting type of hemlock ring-shake follows sapsucker injury.] 


1. Sunscold is the result of sudden temperature change that brings old internal cracks to the surface.

2.  PLD - Post Logging Decadence is results of cutting out the wood from a forest or field.  This so drastically over a short period of time.  Hemlocks have a genetic code for water that does not tolerate logging.  One of the worse things you can do is introduce a species and then turn around and try to eradicate it.  Thus eradicating such a special member of the ecosystem called a forest, that was present here when settlers from Europe arrived, is an obscenity.  We hear so much about violence on so many programs.  But the greatest  violence is called an “OBSCENITY”.  OBSCENITY means that you take away the intrinsic value of any living thing.  You can be obscene to DOG, you can be obscene to a CAT and you can be obscene to a TREE.  

3.  Coal burning and that includes clean or not clean coal.


Reference: Hepting, George, H. July 1971 Disease of Forest and Shade Trees of The United States US. Dept. Agric. Forest Service Handbook Number 386 658 pages.


NOTE:  Hemlock is the only species we know that can go from shade to sun and back to shade and back to sun.  Beeches, can be opened to the sun once yet cannot be shaded again. Yet, has suffered so much resulting in Post Logging Decadence.  They do not tolerate any conditions other then those environmental conditions present before Settlers arrived.  There was no holes in the forest and no organism defined as a pathogen. 

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