Gaines,
Very interesting. Thanks for digging the research up. I anxiously await hearing what others like Lee have to say. ENTS white pine measurers are divided into two camps, the liberals and conservatives. The liberals allow for the possibility of pines in the 250 feet and over class. Conservatives consider 200 feet to be the maximum for the species with an occasional pine getting taller to perhaps 220 feet in historical times. I am a member of the latter group. Bob ----- Original Message ----- From: "spruce" <[email protected]> To: "ENTSTrees" <[email protected]> Sent: Sunday, January 3, 2010 5:18:59 PM GMT -05:00 US/Canada Eastern Subject: [ENTS] White pine growth rates--something of interest about growth possibilities There is some research about the growth rates of white pines that may be of interest to white pine enthusiasts. For a bit of background to make the context of the research I am quoting clear: in forestry, growing sites for various eastern trees are classed by how tall a tree can grow in 50 years. This is called the "site index" for each species relative to each site. For white pine, the site indices range from 60 feet--for a rather poor site--to as much as 120 feet for the best sties. It may be possible that there are some sites with an index of over 120 feet, but if so, I assume they are very, very rare. In fact, most commonly, the best white pine sites are between 90 and 100 feet, which I commonly see quoted for most class II soils. I believe 120 feet is fairly unusual--I know of one just site, a very rich stream bottomland site that is probably a class I soil, that may have that kind of potential. OK, enough for the basic background. Here is the interesting thing I just learned: If a white pine grows 120 feet in 50 years, this same tree on this same superior growing site, after age 55, will not grow any faster than a tree growing on a relatively poor site--index 60. At age 55, both trees--the one growing on the relatively poor site, and the one growing on the very rich site, will be growing at the same rate--roughly one foot per year. So, all the difference between the height of a white pine tree growing on an excellent growing site, and the one growing on a poor site, occurs during the first 55 years. Of course this does not include any factors that may distinguish sites based on factors such as ice and wind breakage. I think this reflects on the question of how tall white pine trees can grow, in that those growing on the very best sites may not grow significantly taller than those growing on the lesser, but still very good sites. Thus, if a growing site is rated at 120 feet, over the life of a white pine tree, the final height of the tree will be just 20 feet taller than a tree growing on a site of index 100. To explain a bit more, if we want to speculate on the possibility of white pines growing to 200, or the oft quoted height of 250 feet, the idea that the 200 plus trees grew on the very best sites, and those sites are now no longer available for growing pines because they are now farmalnd, or whatever, should be less of a factor in our speculations. The difference in the ultimate height of the trees will be only 20 feet or so. So even if we want to argue that the best sites could grow pines taller than what we now see--about 175 feet max--then the potential was for 195 or so, certainly not much above 200, and certainly not 250 or anything like it. This research is summarized (with citatiion) in the USDA Forest Sefvice manual titled "Silvics of North America." The URL is: http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm This is written from a forestry perspective, but contains a lot of information about tree growth, etc of interest to any tree lover. --Gaines Mcmartin -- Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] -- Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected]
