Steve and Ed, Yes, I know some history of the NY Botanical Garden Forest.
This 50 acre forest running along both sides of the Bronx River was never clear cut for farming or timber. It belonged to the Lorillard family who ran a tobacco manufacturing mill (they constructed the waterfall). The land ownership went directly form the Lorillard's to NYBG in the 1890's. The development of trail systems, the devastation of the chestnuts and elms, the large amounts of people going through, and all the hostilities of rapid urbanization were definitely stressors on the hemlocks throughout the 20th century. Their seeds have very specific germination requirements and canopy gaps (from chestnut and elm deaths plus the construction of trail systems) opened the space to shade-intolerant competitors, and the practice of removing of decaying logs from the forest floor changed the composition of the soil. Soil compaction and erosion caused by foot traffic certainly weakened the mature trees further. In the 1930s, the Garden began planting saplings in the groves to make up for the lack of natural seedling establishment. There were some issues with the Hemlock Scale. I can't find data on this. I've included a link to pictures of the spatial changes from 1937, 1985, and in 2000. Note that even though the hemlocks were in decline before the HWA, with the arrival of HWA c.1990, 40% of the extant trees were dead by 1995. In 2009, there must be under 20 trees, if that, and I have yet to find on that is not infected. How does my assessment sound? Let me know if the pix are too dark or didn't come out. http://picasaweb.google.com/JennifDudley/HemlockData?authkey=Gv1sRgCKeP4bGc4qCaSA&feat=directlink Jenny On Mar 27, 9:17 am, "Steven Springer" <[email protected]> wrote: > Hey good thoughts here regarding the demise of the hemlocks in the 1906 > postcard, however, I would argue against the premise that all conifers are > considered pioneer species in forest succession, hemlock is not. Consider > this, pioneer species are not shade tolerant, hemlock is, pioneer species are > short-lived (typically 50-60 years) hemlock is longer lived (some up to 600 > years depending on site dynamics). While the only reliable determination for > tree age is limited to ring-count, I would hedge that the hardwoods in the > current photo are not older than 60-75 years. This would line up with > potential HWA demise time period of the hemlocks within this region of the > country. Does anyone know the HWA history of this park? > > Steve Springer > Urban Forester > City of Bartlett > > -----Original Message----- > From: [email protected] [mailto:[email protected]] On > Behalf Of Will Fell > Sent: Friday, March 27, 2009 7:18 AM > To: ENTSTrees > Subject: [ENTS] Re: Hemlock view 1906/2009 > > That is a beautiful area....it is great the city saved it as a park. > While the HWA is taking it's toll on the hemlock, I would suspect that > the demise of the hemlocks in the old postcard probably predated the > appearance of the HWA. Many conifers are frequently replaced by > deciduous trees in an undisturbed forest, unless there is some > disturbance or other factor such as frequest fire the holds the forest > in a subclimax stage like the outer coastal plain of the southeast. > > What is the purpose of the cables and banners over the river in the > background? > > On Mar 26, 5:17 pm, JennyNYC <[email protected]> wrote: > > Hi, > > > Ed suggested I take current pictures of the sites of the old postcards > > I posted earlier of NYBG in the early days. Here is a colored photo > > taken in 1906 and 3 pictures in the exact same location taken > > yesterday. Even though the hardwoods have not leafed out, it's > > apparent what is sadly missing.... > > > Jenny > > >http://picasaweb.google.com/JennifDudley/HemlocksThenAndNow?feat=dire... --~--~---------~--~----~------------~-------~--~----~ 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] -~----------~----~----~----~------~----~------~--~---
