Unappreciated Neighbors 



Our Underutilized Native Trees 



Stan Knowles 



Perhaps the most striking feature of a tree is its 

 fall color. Fall is when most people take a long 

 hard look at trees. Photographers scramble to 

 get exceptional shots of trees in their fall dress. 



Our native Red (or Swamp) Maple is absolutely spec- 

 tacular in the fall, ranging from greenish-yellow to yellow 

 to brilliant red. Perhaps it is the variability of fall color 

 that causes us to shy away from using it in an urban set- 

 ting, or maybe it's the tree's intolerance to highly pol- 

 luted areas. Dirr advises that it is only intermediately 

 tolerant of sulfur dioxide. Despite these disadvantages, 

 it is very tolerant of soils, although in its natural setting, 

 it is often found in swamps. But some of the best natu- 

 ral specimens of Red Maple are found on upland well- 

 drained soils, so it does have potential for use in many 

 urban settings. In addition, Red Maple is moderately tol- 

 erant to salt, unlike its counterpart, Sugar Maple, which 

 is very intolerant. 



Red Maple transplants easily from the wild as a small 

 tree or larger specimens may be purchased balled and 

 burlapped for spring transplanting. Despite the fact that 

 it is one of New Hampshire's most common trees, it's 

 not a common choice in urban settings. 



The "Armstrong" cultivar is the upright variety having 

 attractive light gray bark. A planting of four of these may 

 be found alongside the Love Gymnasium on the Philips 

 Exeter Academy grounds in Exeter, N.H. It may reach a 

 height of 15 feet and only 4.5 feet wide in four years, 

 but needs at least 25 square feet of soil area. More than 

 that is desirable, but not always possible. 



Much has been said about avoiding trees that bear 

 nuts for street plantings. However, the nut of Pin Oak is 

 relatively small, (1/2 inch in length) and enclosed in a 

 thin cup. According to Dirr, it is tolerant of city condi- 

 tions and based on its prevalence in the Washington, 

 D.C., and Chevy Chase, Maryland, area, it can actually 

 thrive along busy streets. Some of the trees in that area 

 have reached upwards to 100 feet of height and are very 

 healthy and impressive. Here in Portsmouth, there were 

 many Pin Oaks planted around the city in the 1970s. 

 They are interspersed with the overused Norway Maples 

 on Richards Avenue and have outgrown them. 



The dark-green glossy leaf in summer is a real attrac- 

 tion. As with most oaks, the fall color is variable and fre- 

 quently drab, ranging from russet to red. Another major 

 advantage to Pin Oak is its adaptability to a wide range 

 of soil moisture conditions. Although it prefers well- 

 drained soils, it will grow in wet clay soils as well. It is 

 classified among the faster growing oaks, attaining two to 



two-and-a-half feet of height per year. It does tend to 

 be branchy, but early detection of deformities and judi- 

 cious pruning can assist in maintaining the striking pyra- 

 midal form. 



Pin Oak also possesses a fibrous, shallow root system 

 that makes transplanting relatively easy. This tree is 

 nearly free of disease and insect problems, but will 

 show signs of leaf yellowing when iron chlorosis is a 

 problem. Soil additives can provide corrective action. All 

 in all, this tree has great potential for use in urban areas 

 in New Hampshire up to and including Zone 4. 



It may be a bit risky to refer to white ash as an 

 underutilized native tree, but this species has great pos- 

 sibilities, except when the "ash leaf rust" is prevalent in 

 the seacoast. Spartina (or cordgrass) which grows in the 

 salt marshes is the alternate host of the rust disease 

 that infects white ash leaves, petioles, and green twigs. 

 The disease was a problem in the New England seacoast 

 area about thirty years ago and destroyed several white 

 ash trees in Kittery, Maine. However it has not been a 

 problem of consequence since that time. 



Vigorous white ash trees are less susceptible to some 

 of the insect and disease problems that commonly at- 

 tack the tree. The secret then is to plant it on deep, 

 moist, well-drained soils in full sun. It would not be an 

 ideal choice as a street tree because it grows to 80 feet 

 (and occasionally 120) at maturity, but it is a fine speci- 

 men for parks and other relatively large areas. The fall 

 foliage of white ash is a spectacular yellow to deep 

 purple and maroon. An ash in deep purple fall color 

 would be outstanding with a stand of aspen as a back- 

 ground. We are limited only by our lack of imagination. 



Black Gum, Sour Gum, or Black Tupelo, as it is fre- 

 quently called, is rarely used as an ornamental in south- 

 ern New Hampshire. The late |eff Smith of Hollis had 

 much praise for this tree and grew seedlings in the Bea- 

 ver Brook tree nursery with the intent of planting them 

 in the parks around Hollis. Not to overuse Michael Dirr 

 as a reference. Black Gum is "one of our most beautiful 

 native trees: somewhat pyramidal when young with 

 densely set branches, some of which are pendulous; in 

 old age the numerous spreading and often horizontal 

 branches form an irregularly rounded or flat topped 

 crown". 



Do you remember the two outstanding specimens at 

 Spruce Pond Camp, on the edge of the Softball field in 

 Bear Brook State Park in Allenstown? If not, it's worth 

 the trip to see them. They are old trees with bark that 

 conXmueA on page 19 



February & March 1995 



