(3/16) My original plan for this article was to write about one tree. While I was looking for specific information on that tree I happened upon a wonderful book that describes 80 trees worldwide that have very unusual traits--for good or bad. Now I had a different problem: how to choose just three or four trees to spotlight. "Trees are one of humanity's most constant and varied companions." This quote is from Jonathan Drori's new book Around the World in 80 Trees which was published in 2018.

Argan Argania spinosa Don't look for this tree in America--it grows in Morocco and is typical of a desert tree with tough leaves, thorny branches, and is slow-growing. Why would a goat choose this tree? It's after the golden fruit which is oval shaped, the size of a plum. It contains a nut which protects two small oil-rich seeds of argan oil. The oil is used for food and cosmetics. And the goats also like it. In a desert, necessity is the mother of invention; ergo, the nimble goats learned to climb trees.

Beech Fagus sylvatica Specifically this is the European Beech, common in Germany and western Europe but the appearance of European and American Beech, Fagus grandiflora, is very similar as it pertains to the bark. Once you have spotted a beech tree you won't forget its appearance--often described as elephant skin--grey and smooth. Most forest trees have bark that changes in appearance from rather smooth to thick ridges and furrows on a mature specimen (imagine the bark of a northern red oak). As the tree grows taller it also grows in circumference. Over time if the initial outer bark can't stretch or grow quickly enough it splits and breaks apart and the thick and deep furrows of a mature tree become very apparent. Beech tree bark expands sideways to accommodate growth; it sheds its old skin constantly by stretching horizontally and shedding its top layer in tiny fragments.

Alder Alnus glutinosa I chose the Alder because I bought one on impulse and surprisingly it has done well--stayed narrow and rather slow-growing with mauve colored buds and drooping catkins. The special thing about Alder is that it loves water--not that I paid any attention to that when I bought it! It grows well on river banks and sodden places and it must have loved our past year of too much rain. Alder wood is special because in the twelfth century the inhabitants of Venice realized its special properties: as long as alder wood remains completely submerged it will keep its compressive strength for hundreds of years. The Venetians realized that alder foundation piles could stay strong enough to support great buildings "and they had the monumental chutzpah to turn that knowledge into a dream city in a lagoon." (Jonathan Drori) Seven hundred years later, the city is still supported by the oak and alder piles that were the beginning of Venice.

The next three descriptions may be of more personal interest to us as gardeners:

Neem Azadirachta indica This tree is a tall evergreen that thrives in arid areas and infertile soil in India. It yields an oil that according to folklore is a homegrown remedy for almost every ill. It can be chewed or hung in village doorways as protection for those inside. This may be superstition but there is strong science about its ability to modify the behaviour of insects. The neem tree bark, leaves, and oil contain a biochemical battery of insect repellents and steroid-like chemicals which affect the life cycles of insects that may attack trees. It's intended for use on outdoor and greenhouse agricultural food and ornamental crops as an insect repellant and insect growth regulator. Based on the data reviewed by EPA, Cold Pressed Neem Oil will not cause adverse effects to humans and other non-target organisms when used according to label directions.

Tree of Heaven Ailanthus altissma We may wonder why anyone would want this tree but as with many plant choices, experiments, or misplaced enthusiasm, we are now stuck with it. It is native to China and when it was introduced in 1820 in New York State it impressed plant collectors with its generous shade and unfamiliar ornamental quality. It grows almost anywhere, copes with industrial fumes, is drought tolerant, and it smells bad! Most important--it is hugely invasive--think of Rte. 30 between York and Lancaster when you are driving alongside large areas of Tree of Heaven trees. If it is cut down, the stump can resprout at a rate of one inch a day or 13 feet in a season. If it is burned or poisoned, it may send out suckers from the mother tree and it can clone itself indefinitely. It is the basis for the book by Betty Smith, A Tree Grows in Brooklyn.

Wild Apple Malus sieversii The wild apple is native to the forested slopes of eastern Kazakhstan. It shares many characteristics of our present-day apples: familiar foliage, plentiful fragrant white or pink blossoms and it needs other trees for pollination. The remains of the flower can be seen at the bottom of every apple. Wild apples make up just one species and there is great diversity in the size and shape of trees, the size of the fruit (even on the same tree), and the taste of the fruit (even on the same tree). As every consumer and supermarket knows, the apples must be very similar to attract buyers and they must be blemish-free, and each apple must taste almost the same. Because of our 'pickiness' apples have been bred for flavor and size and now we have less genetic diversity because global agriculture has focused on just a few dozen edible cultivars and few cloned rootstocks. We now realize we need new traits such as disease resistance without using expensive or unpleasant pesticides, longer storage, or later ripening, or drought tolerance--traits which may not be available in our current hybrid varieties. The common problem is loss of habitat of the wild apples with the genetic diversity that we need. Seeds are being stored but more is needed to keep the original stock of apples available to encourage diversity.

I hope that having read these short blurbs about several unusual trees you may decide to delve deeper into the following references for more information.

• Around the World in 80 Trees , Jonathan Drori, 2018, Laurence King Publishing Ltd, London
• Bark A Field Guide to Trees of the Northeast, Michael Wojtech, 2001, University Press of New England pps. 7-19
• Neem information:
• http://npic.orst.edu/ingred/neemoil.htm
• https://www3.epa.gov/pesticides/chem_search/reg_actions/registration/fs_G-127_01-Oct-01.pdf
• https://www.peststrategies.com/pest-guides/chemicals/neem-oil/

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