Saturday, November 21, 2009

A new field guide for trees

Wintery view from my trail up Mt. Sentinel a week ago.

After a few rain and storms came through our area in the past few weeks all of our plants have pretty much finished their season. As I mentioned last month an early freeze led to many of our trees having their leaves killed before they were hardened off, so we still have most of our ornamentals, such as Norway maple and European mountain ash with most of their leaves still on the trees. But Montana natives are pretty much ready for winter. So am I, all we need is some snow!



Two weeks ago I was able to visit coastal Alaska, near Ketchikan along the coast. Winter has definitely arrived there, but interestingly they have had a relatively mild November (it was warmer than Montana). All the leaves were gone from the trees except for a few willows and alders that were protected from winds and rain. Lots of adventure traveling there this time of year, you never know if your plane will make it on time with all those storms, fog and rain. Ironically my biggest problem was getting back to Montana with fog covering the airport there…



This month I thought it would be useful to mention some new books coming out that should be interest to all of you
doing phenology observations, and also just for general interest in learning more about the natural history of our trees and plants. A few weeks ago I got a review copy of the new “Sibley Guide to Trees”, published by Alfred A. Knopf, and available in most bookstores. This is Sibley’s first entry into the tree field guide area. David Sibley is legendary among bird watchers for the beautifully detailed illustrations and overall usefulness of his bird guides. His books in fact set a new standard in field guides when they first came out.

This is a pretty ambitious field guide since it covers nearly all native tree species to North America, and also most common cultivated trees and even some shrubs. So for budburst this is a great reference to most of the trees people make observations on, and since it covers so many species this makes it easy to tell if what you are observing is actually the native species or some closely related ornamental, for example. The other thing that is really useful here is that this book also works hard to cover all the flowering and fruiting stages of most groups of trees. This is something that is often lacking in other tree guides, and particularly useful for people making phenology observations. Also it includes illustrations of the variation in shapes and sizes of leaves so you can easily get an idea of how each species varies (something that drives people crazy – leaf shape and size can be so variable!). This is not a technical guide, so if you are interested in getting into all the details and having more definitive information on identification this is not the right guide for you.

For a more technical guide to trees of North America you can consult for example John Farrar’s “Trees of the Northern United States and Canada”. This is more of a desktop reference, but includes lots of photos, more descriptive information, and technical keys, when necessary. This does not help much if you are in the southern part of the country, but for northern areas this is a good one to have. I also recommend Allen J. Coombes book “Trees” which is the in the Smithsonian Handbooks series. This book offers simple keys and clear beautiful color photos of all of the species covered. In this book the focus is on commonly cultivated trees in temperate areas. This is a great supplement to Sibley’s book when you are looking at street trees or trees in parks that may be exotic species (which at times can be easily confused with native species. For winter tree ID I still find George Petrides books in the Peterson Field Guide series on the of the best, since you get nice silhouettes of each type of tree as well as good information on bud and twig ID which will be pretty handy until the leaves come out next spring!














Western serviceberry twig