76 FORESTRY INVESTIGATIONS U. S. DEPARTMENT OF AGRICULTURE. 



Alabama and Mississippi, where, upon the same area, with a smaller number of trees, the crop of 

 timber may be considered almost twice as heavy as that found on the pine barrens proper farther 

 south. On the soil of fine, closely compacted sand, entirely deficient in drainage as found in the 

 so-called pine meadows along the coast of western Florida, Alabama, and Mississippi, as well as 

 on the siliceous rocky ridges of central and northern Alabama, the tree is so stunted as to be of 

 little or no value for its timber. 



"It is neither temperature alone, nor rainfall and moisture conditions of the atmosphere alone, 

 that influence tree growth, but the relation of these two climatic factors, which determines the 

 amount of transpiration to be performed by the foliage, and again with most species we must place 

 this transpiration movement into relation with available soil moisture, in order to determine what 

 the requirements and the most suitable habitat of the species are" (B. E. Fernow). Hence we find 

 that east of the Mississippi River the longleaf pine occurs in greatest frequency along the isotherm 

 of 60° F. ranging to 34° north latitude, while west of the Mississippi it follows a line between 

 the isotherms of 63° and 04° F. and is scarcely found north of the thirty-second parallel of north 

 latitude. Within this area of its distribution it is exposed to wide variation of temperature and 

 moisture conditions. 



Under the influence of the vapor-laden breezes from the Mexican Gulf and an evenly dis- 

 tributed rainfall ranging from 42 to G3 inches during the year ? the longleaf pine appears of the 

 same thrift and vigor of growth in the interior of Alabama under 3.4° to 35° north latitude, 

 with the thermometer falling as low as 4° F. (16° 0.) and a range of temperature of 93° (at Tusca- 

 loosa), as it is found in the subtropical belt of the coast with a maximum temperature of 105° F. 

 (40° O.) and a range of temperature of 94° west of the Mississippi Biver, although the temperature 

 reaches rarely a minimum of 15° and 12°, respectively, at the northern limit of the tree in these 

 States, the diminished humidity of the atmosphere and lesser rainfall, particularly during the 

 warmer season, account for its absence. There can be no doubt that the greater exposure to the 

 violence of the sudden gusts of dry and cold wind known in Texas as "dry northers" exercises 

 also no small influence in limiting the longleaf pine. 



Associated species. — The longleaf pine is eminently a gregarious tree, covering areas of wide 

 extent, to the almost complete exclusion of any other species. In the flat woods of the coastal plain, 

 particularly near its northern limit on the Atlantic slope, it is not infrequently associated with the 

 loblolly pine; iarther south and along the G-ulf coast to the Mississippi liiver, more or less fre- 

 quently with this tree and the Cuban pine. In the upper part of the maritime pine belt it not 

 rarely occurs together with the shortleaf pine and the loblolly pine intermixed with the deciduous 

 trees of the uplands, viz, the black oak, Spanish oak ? black-jack, bitternut, mockernut hickories, 

 and black gum. 



It will be apparent, from what has been said regarding the demands for light, that the asso- 

 ciated species must be either slower growers or later comers, if the longleaf pine is to survive in 

 the mixture. As has been pointed out elsewhere, with the culling of the longleaf pine from the 

 mixed growths it must soon cease to play a pait in them, since its renewal under the shade of the 

 remaining associates is impossible. 



Enemies. — The greatest danger threatening the existence of the forests of longleaf pine must 

 be ascribed to the agency of man, since their destruction is caused chiefly by the reckless manner 

 in which they are depleted without heed to recuperation. The right of ownership has been gen- 

 erally acquired on such low terms that since no value has been attached to the land without the 

 timber, despoliation has been carried on with no other object than the quickest return of 

 pecuniary profits. 



Exploitation. — Such management could not but enfail tremendous waste, a large percentage 

 of the body of the trees felled being left on the ground to rot or to serve as fuel for the conflagrations 

 which scour these woods almost every year. Infinitely greater than the injuries inflicted upon the 

 forest by the logger and hy getting out cross-ties and hewn square timber, which consist chiefly 

 in the accumulation of combustible waste, are those caused by the production of naval stores. 

 When the fact is considered that the production of the 40,000 barrels of spirits of turpentine, 

 which on an average during the latter half of this decade annually reached the market of Mobile 

 alone, implies the devastation of about 70,000 acres of virgin forest, the destruction cfrtuted by this 

 industry appears id its fall enormity, XJader the mauagw^nt of th$ tmmmMm <m<MmM 



