March, 1931] LAND SURVEY OF DURHAM 11 



Sncli aroas arc usually extensive, sometimes exeeeding 100 acres in a 

 block, while the better type of pasture is apt to be in small lots, often 

 near farm buildings. 



Woodland. The woodlands of the town fall conveniently into three 

 subtypes : pure white pine, pure gray birch and mixed hardwoods. Of 

 course, a "pure" pine stand would have other species present, but more 

 than half of the sui'face of the gi-ound would be covered with pine. 

 Since the trees were seldom so thick that all the ground was covered, 

 considerably more than half the trees, and usually practically all, were 

 pines. CJi'ay birch is commonly associated with young pine stands, but 

 it is intolerant, and only a few are found in mature pine. Red oak 

 and both sugar ami red maples are the most counnon hardwoods, with 

 elm. hickor^^ black birch and beech frequent, and all of the other 

 hardwoods scattered. Of the softwoods, hemlock is the most common, 

 with red pine the only other timber producing softwood. Pitch pine 

 and red cedar are not unusual, but are of little value except for cedar 

 posts. Pure or nearly pure stands of pitch pine occur in a few places. 



The pine type is found under a wide variety of conditions but 

 prefers the higher, well drained slopes. Commonly it is in small lots. 

 but sometimes, where cutting has not been too clean, areas of fifty acres 

 or more are found. Of the merchantable stands, the better ones are 

 reserved, as the groves along the bay and the College Woods. Most of 

 the rest was inconvenient to cut. The pine lands raised for timber are 

 usually cut as soon as they can be sold, at about 40 years, when they 

 yield only the poorest lumber. Only 188 acres have reached the 50- 

 year class or better, and at least 80 of that is reserved. 



The fact that the pine stands are largely pure increases the damage 

 done by insect pests and fungous diseases. The worst of these are the 

 pine weevil, Pissodes strobi, and the blister rust, Cronartium ribicola. 

 The weevil is responsible for the dead leaders common in all young 

 stands of pine, especially in the open. The damage from blister rust 

 is well known. 



Gray birch, which is a minor type, results from the prolificacy of 

 birch in seeding in distant areas, such as cutover devoid of tree growth, 

 and burns. There is usually an understory of pine, which often is thick 

 enough to dominate the birch as it grows older. A few other species 

 may intermingle but are only scattered. 



The mixed hardwood type is the most extensive at present because 

 in many instances pine was cut clean and hardwoods seeded in, usually 

 with a few pines. At least 1650 acres, and possibly twice that, were 

 mismanaged in this way. In wet hollows with clay soils, and in wood- 

 lots where hardwood has been grown for fuel for the farm, hardwoods 

 have dominated all along. On the swamp lands which are wooded, red 

 maple and elm are most common, usually raised on hummocks above 

 the surface of the water. A few pines and more hemlocks are apt to 

 be present, and a scattering of other hardwoods. 



On the uplands, almost any combination of species is possible. Red 

 and sugar maple, red and white oak, gray and black birch, beech and 

 white pine are the most common, with hickory, hemlock, blue beech, 

 white ash, basswood, black cherry, trembling and large toothed aspen, 



