AJ- To say nothing of the classic symbiotic relationship between Clark's nutcrackers, whitebark pines and grizzlies!
-Don > Date: Tue, 12 Jan 2010 12:18:35 -0500 > From: [email protected] > To: [email protected] > Subject: Re: [ENTS] Projected heights and Jenny's wrath > > You and Gaines are definitely going to be sent to the "Bird Sensitivity > Re-education Camp". Let's see, we'll make you wear aprons and hand feed > baby bird orphans from dawn to dusk with eye droppers. It will be fun. > > Maybe this will help. I recall reading a theory that the acorn caching > behavior of blue jays was responsible for rapidly pushing oak species > north following the last major North American glaciation. Jays have been > documented caching acorns up to 8 miles from a source tree. They don't > remember where they put all their acorns and are very effective at > planting oaks. Some great studies have been published showing how insect > foraging bird species in Colorado ponderosa stands have an important > role in reducing insect load on pines and thus improve the health of the > trees. Birds have a huge beneficial role in forest ecology. > -AJ > > [email protected] wrote: > > Andrew, > > > > I'm sure that you'll get kudos and credits in Jenny's avian > > sensitivity rating system. But Gaines and I may be in trouble. We'll > > mend our ways. At 68 1/2 I can still change. Really I can. I think I > > can. Maybe I can. > > > > Bob > > > > ----- Original Message ----- > > From: "Andrew Joslin" <[email protected]> > > To: [email protected] > > Sent: Tuesday, January 12, 2010 11:15:28 AM GMT -05:00 US/Canada Eastern > > Subject: Re: [ENTS] Projected heights and Jenny's wrath > > > > That's funny! I've been a birder for more than 20 years. As a climber I > > frequently visit the tops of white pine. In my area in eastern > > Massachusetts I can very confidently say that damage to tops is > > primarily from weather. Over the years I've seen many large raptors > > perched in white pine and have never seen them break anything. I've even > > seen a pair of Red-tailed Hawks mating in the top of a white pine, you'd > > think this rambunctious activity would do some damage but no. I can > > imagine perching birds breaking delicate tops on smaller conifers but on > > mature white pine for example any branch thicker than an inch is going > > to support Red-tailed Hawk (our largest common raptor). I have seen > > red-tails intentionally breaking small branches off of red oak for nest > > material but they don't seem to go for the uppermost branches when > > they're doing this. They need a secure perch on a thicker branch to get > > into position to break a small branch. I can imagine a bald eagle easily > > breaking out some top branches but their population densities are not > > enough in the east to make a difference for our tall white pines. > > -Andrew > > > > [email protected] wrote: > > > Gaines, > > > > > > Oh boy, I hope a rift doesn't develop here in ENTS. Those of us > > > obsessed with tree heights will naturally want to limit damage by > > > birds perching in the crowns, especially their highest parts. I'm > > > definitely not suggesting anyone get out his/her youthful slingshot, > > > but in time the temptation could grow. Giving this line of thinking a > > > foothold could prompt Jennifer Dudley to establish a bird safety > > > patrol to keep a close eye on us measurers. Jenny's wrath would be > > > swift and terrible. Resist the temptation Will. Resist the temptation > > > Scott, John, Dale, .......... Resist. Resist. > > > > > > Bob > > > > > > > > > > > > ----- Original Message ----- > > > From: "Gaines McMartin" <[email protected]> > > > To: [email protected] > > > Cc: [email protected] > > > Sent: Tuesday, January 12, 2010 10:07:42 AM GMT -05:00 US/Canada Eastern > > > Subject: Re: [ENTS] Projected heights > > > > > > Jess: > > > > > > I had thought about mentioning it before, but when you say that the > > > growth rate of a pine tree is influenced by its current height, you > > > bring up an important consideration. Strictly speaking it is better > > > to say that growth rate is influenced by age, and it is this > > > relationship that the growth curves are representing. > > > > > > But the growth rate/height relationship is something that is too > > > often ignored. Years ago I read a report of a provenance trial of > > > white oine, that said that the best way to measure results is not the > > > height of the trees after some set period of time, but to measure > > > their growth rate at various specific heights. The idea behind this, > > > if I remember rightly, is that different sites, including microsites > > > (my term) influence the early growth of the seedlings differently, but > > > this influence is minimized in the data if the growth rates of trees > > > are compared when they are at the same heights (comparably > > > established, comparably developed). And this kind of measurement would > > > best predict the trees’ overall growth potential over time. > > > > > > Now the data that prompted me to open the white pine growth topic > > > showed that the growth rate of white pine on the better sites declines > > > more rapidly than that of white pine growing on the poorer sites, so > > > much so that after age 55, the growth rates are the same—one foot per > > > year. I thought this had some application in the discussion of > > > whether or not white pines could, or did grow to 250 feet. Thus if > > > the fastest growing pines maintain their relatively fast growth rate > > > for only 55 years, then the best growing white pines would not grow as > > > much taller than white pines with more ordinary growth rates as we > > > might have thought. White pines 100 feet tall in 50 years is good, > > > but “ordinary.” Growth of 120 feet is excellent, but after gaining 20 > > > feet over the more ordinary trees in 50 years, and maybe a foot or two > > > in the next five, no further advantage will be gained. All that made > > > me think 250 foot white pines, if view of the fact that none exist > > > today, less likely than I might have thought. > > > > > > Sorry—I said all that before. But I wanted to re-establish the > > > context. > > > > > > Now to the height/growth rate relationship: lost is the above data > > > may be the fact that the trees with the most outstanding growth will, > > > in spite of any decline in growth rates down to the level of other > > > white pine trees after age 55, still be growing faster at any specific > > > height. > > > > > > Of course as Will and others have pointed out, there is the risk of > > > storm damage. I would add to that the damage from large bird perch. > > > The bird perch issue is not recognized by all foresters, but I have > > > observed it first hand many, many times. The tallest trees in my pine > > > and spruce stands are the ones usually hit. The new growth is often > > > completely mashed down. If this happens early enough in the growing > > > season, especially with the Norway spruce, a leader can be > > > re-established. I can imagine that slower growing very tall old trees > > > would have some difficulty doing that, and the damage could > > > accumulate. This would be a significant influence on the ability of > > > older, very tall trees to make good further progress upward. > > > > > > This relates to the ability of second growth stands to exceed the > > > growth of trees in the virgin forest. I will take this up in my next > > > response. Enough for one post here already. > > > > > > --Gaines > > > _________________________________________________________________ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/196390707/direct/01/
