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Library›Open textbooks›Trees and forestry›Pages 25–32

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Trees and forestry · Text

Pages 25–32

CC0 1.0 · Public domain digitisation (CC0) · approximately 4 min read

FIG. 20. STUDY OF OAK WOOD 23 Pith rays of a log seen in cross and radial cuts and at the line of meeting of the two surfaces

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Spt re 1D N INTHEPACIFICFOREST FIG, 22, (Incense Siskiyou County, California. se Cedar and Red Fir, Virgin growth of Incen Cedars in the centre, Red Firs at right and left). ForestryHall irency, re Seecoloredtransp

26 AMERICAN MUSEUM GUIDE LEAFLETS broad; in maple, elm and ash they are moderately broad; in willow, they can be discovered only by means of a magnifying glass. The presence of the pith rays proves descent from more primitive trees of much less strength of trunk, their bulk being made up of pith as are the stalks of corn of to-day. Pith rays are lines of weakness in the trunk; especially are they such inthe lumber. Boards cut with the pith rays (radial or quartered) are, of course, less liable to warp and split than are those cut across them (tangential). FORESTS, THE WEALTH AND THE NECESSITY OF THE NATION RIGINALLY the people of America possessed great forest wealth which they did not realize exhaustible, wholly ignorant of the country’s growth in population and industries. ‘To-day a timber famine is in sight, and there is still far too little realization that this forest wealth is exhaustible; we are destroying annually three and a half times as much wood as new growth adds. Unless all forests from this time on are managed according to some system which will no longer exhaust, but instead, will reconstruct, it is thought that twenty vears will see the end of the timber supply in the United States. The original forests covered 850,000,000 acres; at present 550,000,000 acres! are forest lands but in large part the trees represented in these forests have only a fraction of the commercial value of those of the primeval forest. (See Figs. 21 and 22.) An eyen more impressive view of the situation is given by the following figures, which are averages calculated for the five years previous to 1908, showing the ten countries that lead in the net wood exports and net wood imports respectively:

Countries Selling Wood Tons Countries Buying Wood Tons Russia with Finland 5,900,000 Great Britain and Ire- Sweden 4,460,000 land 9,290,000 Austria-Hungary 3,670,000 Germany 4,600,000 Canada and Newfound- France 1,230,000 land | 2,144,000 Belgium 1,020,000 Norway 1,040.000 Denmark 470,000 United States 1,020,000 Italy 420,000 Roumania 60,000 South America 330,000 India 55,000 Spain 210,000 West Coast of Africa 28,000 Egypt 200,000 West India, Mexico, Holland 180,000 Honduras, ete. 13,000 1ThereportoftheStateCommissionerforJanuary1,1910,givestoNewYorkStatea holdingof1,841,523acresofforestedland,including1,530,559acresintheAdirondacksand 110,984intheCatskills.

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28 AMERICAN MUSEUM GUIDE LEAFLETS Thus it is seen that a large part of the world is getting its wood from Russia, Sweden, Austria-Hungary and Canada. The situation cannot endure, however, for these countries are destroying more forest than they are reproducing. What is in view therefore, is a world-wide wood famine. Disastrous as a wood famine might prove to the industries of the country, it is not the only result attendant on the destruction of forests. The country faces problems of flood, drought and drying winds, of soils washed of their fertility, streams and harbors unnavigable because of irregular water-flow and because filled with tons of silt from soil erosion (Fig. 23), and all of these problems as well as questions of irrigation depend largely for their satisfactory solution on attention to the country’s forests. That they do thus depend lies in the fact that forests convert the region they occupy into a vast ‘‘sponge”’ for absorbing and holding water. It is sa‘d that the Croton Watershed con‘ro'ling New York City’s water supply needs at least 1,000,000 trees planted to husband the rainfall. The 100 Grams | | 100 Grams FIG.24.THEABSORBINGPOWEROFVARIOUSSOILS Diagram to illustrate the relative amounts of water held by various kinds of soil and to show that leaf mould of the forest floor has greatest absorbing power ?OneofthelargestspringwatercompaniesinNewYorkStatehasbeenreforestingits threehundredacresforseveralyearstoprotectitsspringsandmaintainthepurityofthe waterandaregularsupply.Itreportsplanting350,000conifersconsistingoflarch,arbor vite,balsam,hemlockandvariouspines.

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← Pages 17–24Pages 33–40 →

Historical text. Published in 1909. Scientific knowledge, names and medical understanding have changed since; this is a historical source, not current scientific or medical guidance. The text is taken from a digitised scan, so recognition errors from the scan may remain, and plates and figures are not reproduced.

Attribution. Dickerson, Mary Cynthia (1909). Trees and forestry. Digitised text released under CC0 1.0 via Zenodo (10.5281/zenodo.16355593). CC0 1.0. Original source ↗. Text extracted from the digitised PDF without changes to wording; page images, figures and plates are not reproduced. OCR errors in the source scan may remain.

In this chapter Contents

  • Pages 1–8
  • Pages 9–16
  • Pages 17–24
  • Pages 25–32
  • Pages 33–40
  • Pages 41–48
  • Pages 49–56
  • Pages 57–64
  • Pages 65–72
  • Pages 73–80
  • Pages 81–88
  • Pages 89–96
  • Pages 97–104
  • Pages 105–107

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