May 14, 2008

Tree Walk: BART parking lots & spring buds and flowers

Could parking space become the next living space? asked Elsa Brenner of the New York Times in an article of the same name. Brenner wrote of a Westchester County Department of Planning study that proposes to increase housing for moderate-income households by building on office park parking lots. Brenner, quoting from the study, notes that office parks, constructed with roads and utilities, lower development costs on these sites.

Where do trees fit? Well, the article (I am really enjoying my Times subscription) reminded me of photographs I took of the North Berkeley and Ashby BART parking lots. I'd like to share some thoughts about both lots. First, note the large stature trees, pictured below, that provide visual privacy between the North Berkeley station and houses to its west. Also note the small stature trees, pictured above, in the expanse of asphalt on the western side of the North Berkeley BART station. Then, compare the shade profile of a short stature tree, in this case, a purple leaf plum to that of a larger stature tree, a sweetgum (photo below). Importantly, the sweetgum is not at its mature size.

My look at the two BART station was not a compare and contrast exercise. I did not photograph the western parking at Ashby BART which more closely resembles the North Berkeley station. I did photograph the eastern lot at Ashby which has remarkable trees, pictured below.

_________________________________________________________ Spring has definitely arrived. In its earlier days I meant to post about buds, leaves and flowers. Better late than never. The following material is quoted from two of my favorite botany books: Botany for Gardeners by Harold William Rickett and Trees: Their Natural History by Peter Thomas.

This is a bud. This complex structure, beautifully and symmetrically formed of successively overlapping young leaves and including the apical meristem of a stem-all this is comprised in that simple three-letter word. Any bud is potentially a length of stem with the leaves that will adorn it. As the cells lengthen, forming a region of elongation, the leaves which were at first so close-packed at the tip become separated. The cells which were once included in the shirt, broad meristem of the apex now form the length of stem beneath the tip; and leaves which were once crowded on the apex are now attached on the sides of this length of stem, often at wide intervals.

Buds of different trees vary in just how much of the next year's growth is preformed. In fact buds can be divided into three types of growth. In trees such as ashes, beech, hornbeams, oaks, hickories, walnuts, horse chestnuts and many maples and conifers, the whole of next year's shoot is preformed. Everything is preformed or fixed in the bud as it develops over the summer to be expanded into a branch the following spring. These species are described as showing fixed or determinate growth. Since everything is preformed, spring growth occurs in a single, rapid flush and is over in just ten days to a few weeks, and then the terminal bud takes on its winter appearance. In many others, however, only some of the leaves are preformed....Trees showing this free or indeterminate growth (sometimes called continuous growth) include elms, limes (lindens), cherries, birches, poplars, willows, sweetgums [pictured above], alders, apples, and conifers such as larches, junipers, western red cedar, the coastal redwood and ginkgo....Growth continues for longer in determinate species but still normally stops well before the end of the growing season, giving time for next year's early leaves to be preformed in the new buds.
While we are considering buds and stems, let's admire some flowers.

Chinese pistache

Norway maple

Buckeye/ horse chestnut

1 comment:

  1. 08/12/08 @ 11:21
    In response to: Tree Walk: BART parking lots & spring buds and flowers
    Comment from : Eduardo Messidoro [Visitor]
    Do you know what type of trees line the
    North Concord/ Martinez BART station?
    They seem to be oaks, they have acorns in Spring.
    but I just don't know.
    Or, do you know who may know about it?
    I have done a search on the net, but no info.
    Thank you.
    Eduardo

    08/17/08 @ 14:57
    In response to: Tree Walk: BART parking lots & spring buds and flowers
    Comment from : Georgia [Member]
    Eduardo, you could contact BART's planning department or if you send a digital photo I will try to identify the tree. Please send the photo to info at localecology dot org.

    ReplyDelete

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