Re: CB (Nov 29 17:10),
You wrote:

Strip bark trees may have only a single good sample point – center of the strip – and two would be redundant – extra work and damage for no significant gain.

and

If an event mediated strip stabilizes in form then there might be a depression in growth for a few years as a result of injury, but the subsequent growth should be ‘normal’

I may be ignorant of some underlying reality, but both of these observations cry out for more explanation.

1) Why do you say injury elsewhere causes “a depression in growth” in the remaining strip? Our direct observations at Almagre were that growth is not depressed but increases in the remaining live strip when other bark is removed. Visibly clear as a growth pulse in the rings for event mediated stripping.** Presumably this is also true for progressive dieback?

2) We did some multiple sampling only a few inches apart on stripbark bcp’s, and found a wide divergence in growth. If there’s only a single good sample point… how can we demonstrate that the single point is any good? How can we correct for the mechanical impact on growth of the dieback/stripbark mechanisms?

3) If these ancient trees tend to go through non-climatic dieback/stripbark processes, and if growth tends to increase in the remaining live area, wouldn’t these combine to form a generalized “recent growth surge” signal among upper treeline — ie most-exposed — tree stands? How can we disaggregate this “mechanical” signal from climate-related factors? This seems a potential general confounding factor in upper treeline studies of all life forms affected by mechanical stripping/dieback processes.

[** This effect makes sense intuitively as well; AFAIK various studies have been demonstrating hormonal (?) communication among various parts of a tree regulates growth in response to such external factors.]