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Sat 4 Apr 2009 - 12:27 am UTC
I couple of years ago I cut down a couple of black walnut trees next to my house. This is a decision I quickly grew to regret. My house now gets much hotter in the summer because I no longer have the shade on the west side of my house that these tree used to provide.
As soon as I cut them down, the tree started growing back from the stumps. They are now between 10 and 20 feet tall, but have lots of little trunks rather than one big one.
I'd like to encourage each of these two trees to gain height as quickly as possible to get back some of my shading.
Here is a photo of what they look like now...
My questions is; what is my best strategy at this point? Should I prune these back to a single trunk each, or let them keep growing as is? Should I fertilize? Water? How much?
Sun 5 Apr 2009 - 8:09 pm UTC
Off the top of my head, I do agree with my colleague redhoss's comment for a primary strategy -- choose one single (strongest or best standing) growth. Also, the option for fast growing trees is worth considering -- however, recovering your black walnut trees is possible and fun (provided that you like doing it) -- admittedly, a bit messy though. I'm collecting supporting information -- not that easy, because all I found so far is not specific for these trees groing from the stumps, while useful all the same. It might also help to know where's your area and the age of the original trees. Thank you.
Thu 9 Apr 2009 - 1:25 am UTC
Well, all the literature I found on the web about black walnut trees' care, confirms the recommendation that redhoss gave you in a comment and I agreed with, this regardless whether the different sprouts are growing from the stump or they developed because of a damaged terminal bud:
Excerpt from the University of Idaho's College of Natural Resources' "UI Extension Forestry Information Series - Alternative Tree Crops No. 3 - Black walnut" by Yvonne Carree Barkley (http://www.cnr.uidaho.edu/extforest/ATC3.pdf ):
"Pruning. Black walnut has a tendency to produce multiple leaders due to frost or insect damage to the terminal bud, so corrective pruning to maintain a single leader and limit the number of developing branches is very important if lumber production is your goal."
Observe that the passage makes a reference to "lumber production", which involves length optimization, just like your own objective, even though your drive is shadow instead of production.
Natural Resources Conservation Service - Conservation Practice Standard - Tree/Shrub Pruning (acre) - Code 660 http://www.marionswcd.org/pdf%20files/tree_shrub_pruning.pdf - Page 2; excerpt:
"A. Corrective Pruning of Hardwoods
"Prune seedlings in the spring before the new terminal has grown more than 3 inches. Remove the multiple leaders and any damaged terminals.
"If a quality seedling is not apparent after 3 growing seasons, cut the tree off 1 inch above the ground during the dormant season. After stump sprouts appear, select the best sprout to leave and remove all others."
North Central Forest Experiment Station 3.01 - Walnut Notes - Corrective Pruning http://nrs.fs.fed.us/pubs/wn/wn_3_01.pdf
"How to Prune
"(...) the objective is to produce trees with single, straight stems while minimizing the amount of leaf area removed so that the vigor of the tree is not reduced.
"If two or more leaders are competing for dominance, remove or cut back all but one so that the selected leader can develop into the main stem. The selected leader need not be perfectly straight and upright at the time of pruning. Removing the competing leaders will allow the selected one to straighten and grow upright after one or more growing seasons."
Now, this that comes next in the quoted webpage, goes straight to the point, when describing a corrective technique which involves cutting off the tree to the stump:
"(...) In coppicing, the tree is cut completely off near the ground. (...) Normally several sprouts will grow up from the stump. Identify the best of these by late June or early July of the same year, and then cut off the other sprouts.
The article ends with this general recommendation that is worth keeping in mind:
"In pruning, it’s not possible to prescribe a standard treatment; each tree must be treated individually. But keep in mind that the least amount of pruning necessary to correct the form problem will produce the best results."
Regarding water needs of black walnut trees, please see the following excerpt from the article "Black Walnut trees: planting and caring" (http://www.landsteward.org/page.cfm/4429 ) by The Plant Man, at Land Stuard (http://www.landsteward.org/ )
"As you might guess, the soil is a major factor in growing a healthy tree. Black Walnut trees will do best when planted in a site that consists of loose, well-drained, loamy soil to a depth of two to three feet with a fairly good proportion of the organic matter known as humus. The roots of your young trees will be able to absorb moisture and nutrients and grow faster in loose, well-drained soil.
"But you can have too much of a good thing – including water, so avoid planting Black Walnut trees in a site that is subject to standing water. And good "percolation" works for trees as well as coffee. In this case, good percolation means that water drains through the soil neither too fast nor too slowly, so avoid "sandy" soil on the one hand and heavy clay-like soil on the other. There are solutions to be found for less-than-perfect soil, so feel free to get in touch with me (see the contact information below) and I might have some suggestions, as well as resources for soil testing labs, etc."
For a more in depth approach to the water issue, see for example the following quotation from the article "Juglans nigra L. - Black Walnut - Juglandaceae -- Walnut family, by Robert D. Williams http://www.na.fs.fed.us/pubs/silvics_manual/Volume_2/juglans/nigra.htm , at the USDA's Northeastern Area State and Private Forestry website (http://www.na.fs.fed.us/ ):
"Walnut is common on limestone soils and grows especially well on deep loams, loess soils, and fertile alluvial deposits. It also grows well on good agricultural soils that do not have fragipans. Walnut grows slowly on wet bottom land and on sandy or dry ridges and slopes. Throughout its range, walnut generally reaches its greatest size and value along streams and on the lower portion of north- or east-facing slopes. This is particularly true near the limits of its natural range."
As to fertilizing recommendations, please see the article "Black Walnut Tree", by Dr.Akhtar Khwaja PhD CPC, CPAg/SS; K Laboratories International Inc, Oshkosh, WI, USA (http://www.kaglab.com/Services/walnut/Black%20Walnut%20Tree.htm ); please note that the figures are given in the scale of a plantation (actually, most of what I've found and posted here was originally written for that purpose), but they can still be a reference for your needs:
"A good fertilizer and soil amendment recommendation for Black walnut tree in soil with neutral pH and medium levels of soil phosphorus, potassium and sulphur is the application of 1000 ponds per acre of Gypsum, and 450 ponds per acre of NPK fertilizer at the ratio of 6-24-24. High nitrogen applications on Black walnut tree is not necessary after three years and even in some soil after two years it is not necessary to apply high nitrogen containing fertilizer. It increases lodging, and breaking the tips and sometime whole trees."
Other articles with more in-depth information regarding fertilizing, from the same source are:
"Soil and Plant Analysis and Fertilizer Recommendations for Black Walnut Trees" by Dr. Akhtar Khwaja Ph.D.(a) and Ruma Roy (b): http://www.kaglab.com/Services/walnut/snpanlys.htm
"Plant Analysis and Fertilizer Recommendations": http://www.kaglab.com/Services/walnut/plntanly.htm
In general, the Black Walnut Tree section (http://www.kaglab.com/Services/walnut/walnhome.htm ) of K Laboratories, Inc. (http://www.kaglab.com/ ) seems to be a useful resource for anything related to black walnut trees.
Tangentially related but useful information to take into account:
Excerpt from the already quoted article "Juglans nigra L. - Black Walnut - Juglandaceae -- Walnut family, by Robert D. Williams http://www.na.fs.fed.us/pubs/silvics_manual/Volume_2/juglans/nigra.htm , at the USDA's Northeastern Area State and Private Forestry website (http://www.na.fs.fed.us/ ):
"Vegetative Reproduction- If small black walnut trees are cut or killed back by fire, the stumps usually sprout. Sprouts originating near the root collar generally are free from defect but sprouts originating high on older stumps often develop heart rot or other decay from the parent stump."
There is an interesting (maybe polemic) article, recommending summer pruning for black walnut trees: "When To Prune Black Walnut Trees", by Scott Brundage, Consulting Forester, in "Bluff Country Master Gardeners", Volume 3, Nº 9, Sept. 2004; http://www.hort.wisc.edu/mastergardener/locals/bluff/BCSept2004.pdf
Also, you might be interested in the following links to general advice regarding black walnut tree pruning and care:
Black Walnut - Juglans Nigra By Vanessa Richins, About.com: http://treesandshrubs.about.com/od/commontrees/p/blackwalnut.htm
Here again: "Black walnut trees tend to form several leaders. Prune the tree so that it only has one central leader."
Black Walnut Nutrition - by Felix Ponder, Jr., USDA Forest Service, Jefferson City, MO; James E. Jones, Hammons Product Company, Stockton, MO; H. E. “Gene” Garrett, University of Missouri, Columbia MO -
"The elements essential for normal growth of walnuts and other green plants have been categorized as major elements, which are required in large amounts, and minor elements, which are required in small amounts. Black walnut requires large amounts of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg), and smaller amounts of sulfur (S), iron (Fe), manganese (Mn), boron (B), zinc (Zn), copper (Cu), and molybdenum (Mo).These elements are considered essential because their absence can be demonstrated to cause injury, abnormal development, or death to the plant."
I believe that the information posted should meet your requirements. If not so, please feel free to ask for clarification.
Thu 9 Apr 2009 - 1:35 am UTC
PS: As an additional resource in case you decide to opt for a faster growing species, please see the article "Fast-Growing Trees - What is a 'Fast-Growing' tree?" at http://www.cdr3.com/nursery/nu00002.htm -- However, please have a look at this statement excerpted from it:
"Some of the other broadleafs that can grow fast include the Pin Oak, Tulip Tree, the plums (Prunus genus) like the Black Cherry and Cherry Laurel, the Elms, Black Walnut, the Locusts, among others."
Fri 29 May 2009 - 5:14 pm UTC
Thank you very much, Josh, for the comment and tip! Best regards,
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