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=3B&nbsp=3B&nbsp=3B& Hi Dave et al., "Sleep-walking into a crisis" is the operative observation. When we have eruptions of native species (spruce budworm, mountain pine beetles, spruce beetles, Colorado potato beetles, etc.) it almost always is indicative of poor forest or agricultural management practices and/or changes to the environment such as those occurring as a result of climate change. The solutions almost always involve addressing the root causes of these problems rather than trying to bandage the symptoms. Such common sense, unfortunately, is frequently in short political supply. ;~> Cheers! Chris On 28-Apr-12, at 9:36 PM, David & Alison Webster wrote: > Hi Rick, Fritz & All, Apr 28, 2012 > Once again I would caution against shooting the messenger. Bark > beetles and Spruce got along fine for untold thousands of years. > Beetle activity is likely a symptom of some underlying problem that > begs for study and perhaps solution. > > Especially over the last 20 years, huge areas of Spruce have died > and this beetle and no doubt other Bark Beetles have been present in > large numbers. But I think the real problem is air pollution; low- > level ozone, acid rain and perhaps other unrecognized air pollutants > (or other stresses). > > In a nutshell, I think our trees die and Bark Beetles have a field > day because the trees are weakened way before their time. > > Consider a few contrasts. > > 1) The gov site says White Spruce matures at about 50 years of age > whereas > http://www.gardenguides.com/taxonomy/white-spruce-picea-glauca/ > says White Spruce lives up to 300 years on good sites protected from > fire and up to 1000 years near the tree line. Native Trees of > Canada (1961)says WS may reach a height of 120' and a diameter of > 4', averages being 80' and 2' respectively. Darn few WS trees reach > 2' DBH today. > > 2) The gov site says to clean up blowdowns ASAP; more than 2 > blowdowns/ha are a prime source of outbreaks as are high stumps, > cull logs and large diameter slash. If the trees were healthy then > having deadwood present, where beetles could feed, would not be a > danger to live trees. > > 3) The gov site says "If the tree is weak from numerous attacks, > little or no sap may be visable." One might perhaps more correctly > reverse these components; "If the tree is weak then little or no sap > will flow when beetles drill holes and attacks will consequently be > numerous." > > 4) The gov site says "When beetle populations are low, the trees are > able to resist attack". Or is it the other way around ? "When trees > are able to resist attack, beetle populations are low." > > 5) The gov site says "Older trees are not able to produce the extra > sap necessary to "pitch out" the invading adult beetle". Amen to > that if "Older" is replaced by "Stressed". > > 6) The pitch tubes mentioned in Detection are I think evidence of > trees so weakened that pitch flows so slowly that it dries before it > can flow downward (and beetles likely get through the layer > containing resin canals before there is enough flow to prevent > entry) . Pitch tubes were numerous in North Alton in 2000. [They > were also mentioned at about this time as being characteristic of > BSLB]. > > We don't need to reinvent the wheel but at least should have > current measures of known problem air pollutants [Is this being > done ?]. There have been numerous studies of e.g. Waldsterben, first > associated with acid rain and more recently with pollutants > generated by high-speed traffic on the autobahn (saw the latter > recently but can't recall where). NS and especially the Valley is > the tail pipe of Eastern North America. > > There have been some measurements of low-level ozone I think but > where and for how long I don't know. Rather than ramble on and on I > will cut this part short by asking if anyone knows the current state > of air pollution monitoring here. > > Why bother ? Well, e.g. if we could show that 80% of our pollution > comes from the US then that could be used as a lever in trade > negotiations.etc or even a basis for compensation. > > Injury caused by air pollutants increases nutrient loss by > leaching from leaves. So a tree that is already weakened has to > expend metabolic energy just to get back to where it was before the > last drizzle. > > We have a 'problem' with disposal of biosolids. It is just > possible that very light applications of biosolids to woodland would > kill two birds with one stone. > > Trying to find answers is I think preferable to sleep-walking into > a crisis which so far as I know sums up Forestry research here over > the last 40 years or so. > > Yt, Dave Webster, Kentville
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