Please Explain: Trees

Friday, September 18, 2009

You may have noticed that leaves have started turning, marking the end of summer. On today’s Please Explain we'll find out why leaves change color and everything else about trees, with Jessica Argate, Forest Manager, New York Botanical Garden, and David Allan Sibley, author of The Sibley Guide to Trees.


Jessica Argate and David Allan Sibley,

Comments [21]

thad davis from kendrick, idaho

I have a fair understanding of why deciduous tree leaves turn color and then drop. But I also have an interest in evolutionary biology and got to wondering just "why" the leaves often turn such brilliant and beautiful colors. Many animals attract mates by the show of colors. So what's up with our deciduous trees? Why so showy?

Nov. 28 2009 12:48 PM
Jac Radoff, The Manhattan Tree Project from 310 West 77th Street, NYC 10024

Mr. Lopate:

replay the part of your program in which Ms. Argate's startling off-the-cuff remark at the end, probably wrong and definitely irresponsible, stated that she can and is controlling Dutch elm disease (DED) in the.
N. Y. Botanical garden with a fungicide. This will make it more difficult to contain DED in Central Park and Riverside Park. She neglected to say how long the anti-fungicidal effects last. The therapeutic effects of Merck's fungicide used in the 1970's were guaranteed for only one year. So if she injects the elms every year,then the basal roots will rot and the tree will die of the injections. DED cannot be controlled without rigorous sanitation! A comprehensive, integrated, and expanding DED program in which the use of fungicides play a relative minor role is what is lacking and needed. Now this will be more difficult to achieve.

Mr. lopate, the people of NYC are badly served by the omission in your influential and widely listened to program of what is really necessary to control DED. I would be pleased to correct the record with her, with you, or with any other non-political expert.

Sep. 21 2009 04:39 PM
Steve from Tennessee

"Grasses" are a collection of species which are related closely enough evolutionarily to be lumped together in the 'grass family' (the Poaceae).

'Tree' is a type of plant growth form, and some grasses arguably could be called 'trees' (or least 'shrubs').

Sep. 19 2009 11:14 AM
Jac Radoff, The Manhattan Tree Project from 310 West 77th Street, NYC 10024

Fungicides alone cannot control Dutch elm disease (DED), as your guest, Ms. Argate, sugests. Rigorous sanitation is vital. Now a comprehensive, integrated, and expanding
DED program will be more difficult to achieve, since your garden expert claimes to have a fungicide to do the whole job. DED cannot be controlled if dead and dying trees are not removed promptly. Repeated yearly injections of fungicide will decay and rot the basal roots, and the tree will die of the treatment. I deserve a chance to fully correct a wrong impression.

Sep. 19 2009 12:26 AM
michael Welt from Amityville

I once heard that bamboo is actually a grass but the guest sounded very sure of herself and is an expert.

Sep. 18 2009 06:55 PM
Lisa from West Orange, (Llewellyn Park) NJ

Greetings! I live in Llewellyn Park, the 150 year old, romantically landscaped community in NJ that is also location of Thomas Edison's home, Glenmont. I just left a landscape committee meeting where we discussed, of all things, trees! We are wondering how to plan for the replacement of our maturing trees, which unfortunately are being lost for a multitude of reasons -- aging, storms, disease, etc. We have many invasives, such as Norway Maples, that we are agressively removing as they prohibit growth of more desirable species. We also have beeches, Oaks, Maples. Do you have any advice for us?

Sep. 18 2009 01:57 PM
Meghan from chelsea

I heard that the U.S. department of agriculture established in the 1950's that trees planted in larger metropolitan areas be males because the female trees were more expensive to clean up after when they produced acorns, sticky berries, and fruits. Besides causing a much higher amount of pollen in cities... Are there any other benefit to having male trees in metropolitan areas? Are we missing out on anything by not having female trees?

Sep. 18 2009 01:56 PM
James Sachs from Yonkers

This may be the wrong show for this question. I have heard from trusted sources that recycling paper may in fact be more harmful to the environment than buying virgin paper. The claim is that recycled paper sales drive down the cost of virgin paper, thus devaluing forests of trees used for paper, which are then sold to developers who build where oxygen producing trees once stood.

Can anyone on the air right now speak on this?

Sep. 18 2009 01:55 PM
Chicago Listener

Are there any national tree-planting efforts or programs or is the work being done on a local level?

Sep. 18 2009 01:53 PM
Jack from Brooklyn

FWIW, the Ailanthus Tree is the literal "tree" of the book "A Tree Grows in Brooklyn." Don't knock it!

Sep. 18 2009 01:50 PM
Andrew from Westchester

I've heard that a number of Walnut varieties are dying due to illness or an infestation of some sort. Since these trees have been such a great source of food and wood for centuries, is there any chance they will become endangered?

Sep. 18 2009 01:49 PM
Helen from Woodside

(appreciating the pun of my town) Would love to hear about the challenges and benefits of "going native" - removing invasives and restoring "traditionals."

Sep. 18 2009 01:46 PM
Orrie from Port Washington, NY

How can I grow an oak tree from an acorn? I just picked up a pocketful of acorns on my daily walk.

Sep. 18 2009 01:46 PM
judith from park slope brooklyn

can you ask the guest to talk about if bamboo is considered a tree?? or a weed (!!) my neighbor has a yard full of it and it is invading MY yard and I can't stop it! It is so invasive and the roots can't be stopped. is there any suggestion about how to stop this?

Sep. 18 2009 01:45 PM
Larry from Nyack

Questions: {1) If a tree limb is pruned at the trunk is it best to let it be or to spray it with black pruning seal? Does the answer depend on the diameter of the removed branch [small vs large]?

(2) Is it better to remove the lowest brances of a 30 year old blue spruce that touch the ground?

Sep. 18 2009 01:44 PM
karen from new jersey

NC Native: "Flowering plants" include plants as diverse as the grass in your lawn to typical annual and perennial flowers and include many trees as well. What you would call the 'petals' of a dogwood "flower" are actually not petals at all, but modified leaves called 'bracts'. The actual flowers are small and located at the center of all of those bracts. As for 'what gives', I would say it is a case of the botanical definition of a flower being different from the 'layman's' definition of a flower.

Sep. 18 2009 01:41 PM
Chicago Listener

I read somewhere that oak trees are the best for enhancing biodiversity, that a multitude of insects prefer to live in oaks and this in turn attracts birds.

Is this true and does it hold across the country?

Sep. 18 2009 01:38 PM
RLewis from bowery

We can walk around a Dogwood, and it has the other characteristics mentioned, but I understand that it's my home state's Flower (NC). What gives?

Sep. 18 2009 01:33 PM
Peter from New York City

Can your guests comment on Freeman Dyson's idea that trees are the best carbon-eating system on the planet, and thus crucial for reducing global warming?

Sep. 18 2009 01:31 PM
katie holten from nyc

running late for a meeting at the Tree Museum - but i'm looking forward to coming back to listen to this later today. I wonder will Jessica mention the Tree Museum on the Grand Concourse!

Sep. 18 2009 12:08 PM
Joe Adams from Bergen County, New Jersey

In my backyard there is a giant ailanthus tree that started as a weed more than 40 years ago and grew like Jack's beanstalk. If records are kept for high ailanthus trees, what is the highest? Are there any uses for ailanthus wood?

Sep. 18 2009 07:34 AM

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