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54 M. L. CAREY (Carey and O'Brien, 1979) but there are considerable differences hetween some of the nutrient concentrations for the two sites. There is also considerable variation between some of the nutrient levels for similar components on different sample trees. For instance there is a 300% variation in the concentration of phosphorus in the dead branches. The variation is equally high for phosphorus concentrations in the roots. These variations are most likely directly related to the difficulties involved in sampling these components (which include bark and wood material) representatively and are mainly responsible for the high error associated with some of the final estimates (Table 5). The data presented in Table 5 have been grouped into the three major crop components, slash, (includes all branches, needles and cones), ~temwood and bark, and roots. As can be seen a high degree of confidence can be attached to the estimates with the exception of the nutrient concentrations in the roots. The estimates of dry matter and nutrient contents are reproduced in Table 6. Included are data on the percentage distribution for each component and on the D.M. and nutrient content of the forest floor. Data are also given for the total nutrient content of the soil to I metre at the site concerned. These latter figures only include the soil fraction less than 2mm in diameter and do not provide any real indication of the amounts that are or may become available to forest trees. However, they do give a broad indication of the total nutrient reserves in the site. Table 6 shows that the wood and bark account for 62% of the total quantity of dry matter in the crop, the slash 20% (71 metric tonnes ha- 1 ) and the roots 18% or 64m tonnes ha- 1 . Although the slash fraction only accounts for one fifth of the total dry matter it contains approximately half of the total quantities of N, P and K in the crop. Its removal from the site under a more intensive harvesting regime than that currently practiced would therefore at first sight appear to have serious implications for site fertility. For instance, if the amounts of nutrients in the slash are divided by the approximate quantities considered necessary to sustain growth (60, 3 and 15kg) it is apparent that it contains the equivalent of about 8 years supply of nitrogen, 15 years supply of phosphorus and 14 years supply of potassium. However, the amounts of nutrients involved are quite small relative to the considerably larger quantities being used nowadays to sustain high production under intensive agriculture. The effects of the removal of the slash ultimately depend on the nutrient and organic matter reserves in the site which in this particular instance are quite large. Reference to Table 6 shows that the nutrient contents of the slash represent less than 3 per cent of the total amounts present in the top 30cm of the mineral soil. Although
Table 3 Dry weights of components of each sample tree (kg). :E :r: 0 r tTl Sample Tree No. 2 3 4 5 6 7 8 9 10 -l ::0 tTl tTl :r: Dead Branches 22.3 29.7 28.6 28.5 29.6 90.9 36.4 61.3 39.2 88.1 :> ::0 Live coarse branch wood 6.6 13.5 17.5 10.7 41.9 36.7 44.0 31.7 50.9 74.3 < tTl Live coarse branch bark 1.0 2.7 8.2 2.1 9.8 10.7 11.7 9.4 9.1 16.9 Live fine bra:nch twigs 7.6 25.3 17.3 16.6 32.5 42.6 46.2 36.1 51.0 52.1 Live fine branch needles 8.9 27.4 18.0 18.2 30.4 46.7 37.6 42 .9 77.8 54.0 Cones 0 0.8 0.9 0 3.1 3.7 0 2.7 5.0 1.6 Bole wood 136.0 232.6 299 .2 280.6 495 .0 529.7 557.5 582.0 549.3 799.2 Bole bark 10.1 15.5 18.5 17.9 30.5 29.3 30.0 40.0 27.5 52.1 Roots 33.0 94.5 95 .0 96.3 155.0 119.7 228.5 208.1 210.0 152.5 D .M. above ground 192.5 347.7 408.3 374.7 673 .7 790.3 763.4 806.1 809.8 1138.2 Total slash D.M. 46.4 99.6 90.6 76.6 147.3 231.3 175.9 184.1 233.0 286.9 C/l -l Z 0 TotaID.M. 225.5 442.2 503.3 471.0 827.8 909.9 991.9 1014.2 1019.8 1290.7 v. v.
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Vol. 37. Ro. 1. 1980 IRISH FORESTRY
Page 3 and 4:
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Page 5 and 6:
WICKWOOD TIMBER PRODUCTS Manufactur
Page 7 and 8:
Poulan Chain Saws From the fastest
Page 9 and 10:
Commonwealth Forestry Bureau , FORE
Page 12 and 13:
Your friend for life ~ Bank 1F1reia
Page 14 and 15:
IRISH FOREST PRODUCTS LTD. 28 Upper
Page 16 and 17:
....... ~ .........................
Page 18 and 19:
PORTLAOISE SAWMILLS MIDLAND FORESTR
Page 20 and 21:
:2 Notes for the Assistance of Cont
Page 22 and 23: Council of the Society of Irish For
Page 24 and 25: The Society of Irish Foresters The
Page 26 and 27: 1.0'DRISCOLL 6~ • var. contort a
Page 28 and 29: \0 J. O'DRISCOLL Most of the commer
Page 30 and 31: 12 1.0'DRISCOLL ~ coastal ~o 0 inla
Page 32 and 33: 14 1.0'DRISCOLL Of the total record
Page 34 and 35: 16 J . O 'DRISCOLL Table 2 - Growth
Page 36 and 37: IX J. O'DRISCOLL region and north a
Page 38 and 39: 2() J.O'DRISCOLL importance, in com
Page 40 and 41: 22 J. O'DRISCOLL Forbes, A. C. 1928
Page 42 and 43: JOHN J. GARDINER In this context it
Page 44 and 45: 26 JOHN J. GARDINER 80 % 60 - --- P
Page 46 and 47: JOHN J. GARDINER profit in its twel
Page 48 and 49: 30 JOHN J. GARDINER 10 Styan, G. E
Page 50 and 51: 32 P. McCUSKER the audience is enha
Page 52 and 53: 34 P. McCUSKER you can introduce hu
Page 54 and 55: Swedish Forestry A Question of Bala
Page 56 and 57: 38 E. P. FARRELL growing stock was
Page 58 and 59: 40 E. P. FARRELL During the late 19
Page 60 and 61: 42 E. P. FARRELL production in the
Page 62 and 63: 44 E. P. FARRELL ,+50,000 in the 19
Page 64 and 65: 46 E. P. FARRELL stimulate the fore
Page 66 and 67: 48 Whole Tree Harvesting in Sitka S
Page 68 and 69: )0 M. L. CAREY METHODS Field: The c
Page 70 and 71: Table 2 Diameter Breast Height, Bas
Page 74 and 75: Table 4 Chemical Analyses Used in N
Page 76 and 77: 5H M. L. CAREY Table 5 Regression E
Page 78 and 79: (,0 M. L. CAREY However most of the
Page 80 and 81: 02 M. L. CAREY idea to consider har
Page 82 and 83: 64 Notes and News The Increasing De
Page 84 and 85: 66 NOTES AND NEWS This forest, the
Page 86 and 87: 6X Letters Dear Sir, A recent meeti
Page 88 and 89: 70 Book Reviews IRISH FORESTRY POLI
Page 90 and 91: 72 BOOK REVIEWS Water by Dr Drew. i
Page 92 and 93: 74 Society Activities ANNUAL GENERA
Page 94 and 95: SOCIETY OF IRISH FORESTERS STATEMEN
Page 96 and 97: 7S SOCIETY ACTIVITIES Other Busines
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Page 100 and 101: FORESTRY COMMISSION PUBLICATIONS Re
Page 102 and 103: I • • WOODFAB •••••
Page 104 and 105: The Irish Timber Growers Associatio
Page 106 and 107: TREE -- PROBLEMS • SOUTHERN TREE
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