No description available.

No description available.

No description available.

Ground based forest inventory surveys can provide highly accurate measurements of tree and stand characteristics, but are time-consuming and costly, and therefore typically limited to number of sample plots.  Estimating tree and stand characteristics from digitised aerial photographs can provide measurements from the whole stand, but is less accurate.  The goal of this study was to evaluate the application of scanned, stereo aerial photography and digital photogrammetry in combination with tree crown delineation techniques to measure tree and stand characteristics in two sites in Scotland, Rosarie and Leanachan forests.  Existing medium-resolution scanned images of true colour aerial photographs (1:10,000) were used to derive Digital Elevation Models (DEMs) of the forest canopy and digital orthophotographs.  Tree crown delineation techniques were used on the derived digital orthophotographs and tree crown measurements including crown area and coordinates of each crown were derived.  The DEMs in combination with Digital Terrain Models (DTMs) derived from digital contour maps, were used for the estimation of tree and stand heights.  Equations derived from regression analysis of individual tree measurements on the ground, and the orthophotographs from Rosarie forest, were used for the estimation of tree and stand characteristics of both sites. For Rosarie forest the estimations of stand top height, basal area, stand volume stand biomass and stand density (~23.7%) were similar with the ground measured stand characteristics (<span lang=EN-GB style='font-family:Symbol'>±10%), where as for Leanachan forest the estimations were less accurate due to the non-optimum illumination conditions during the acquisition of the aerial photographs. The level of accuracy achieved in this study is adequate for measuring tree and stand characteristics, if the acquisition conditions of aerial photographs are optimal.  Higher level of accuracy may be possible, but requires more accurate DTMs, possibly derived using active airborne remote sensing sensors.

No description available.

One part of the afforestation programme consisted of the establishment of an afforestation trial on a bog and fen site in central Newfoundland to determine growth and nutrient response of newly-planted black spruce (<I>Picea mariana</I> (Mill.) B.S.P.) and eastern larch (<I>Larix laricina</I> ((Du Roi) K.Koch). The experimental design was a split-split-plot consisting of surface treatments (untilled, tilled) as main-plot treatments, fertilization (unfertilized, PK) as split-plot treatments and four ditch spacings ( 3 m, 5 m, 7 m, and 15 m) as split-split-plot treatments. A total of 3,960 25-week old container seedlings of each species were planted on each site at spacings of 0.50 m in rows of nine trees, each row being situated at a distance of 1.0 m apart. Surfaces were tilled at 0-200 mm depth using a farm rotovater attached to the back of a tractor. Ditches were made at depths of 0.50-0.75 m with a Dondi ditcher attached to the back of a tractor, and fertilizers were broadcast at the rate of 60 kg/ha P and 50 kg/ha K. The second part of the afforestation programme was a refertilization trial of 1) Japanese larch (<I>Larix leptolepis</I> Seib and Zucc.) and black spruce trees planted on Stephenville bog in western Newfoundland in 1968; and 2) black spruce, white spruce (<I>Picea glauca</I> (Moench) Voss) and lodgepole pine (<I>Pinus contorta</I> Dougl.) planted on Millertown fen in central Newfoundland in 1973. Both sites had been ploughed with a Parkgate-Tyne plough at 1.8 m spacings 1-2 years prior to planting. Following planting of the Stephenville site in 1968, the black spruce and Japanese larch were spot-fertilized (around each tree) with a top-dressing of 57 g of ground mineral rock phosphate. This procedure was repeated in 1970 with 128 g of a mixture of phosphate and potassium (20% P₂O₂, 20% K₂O). On the Millertown site, all trees were spot-fertilized in 1973 with a mixture of 71 g urea, 99 g rock phosphate and 41 g potassium sulfate.

Consistent patterns of foliar N concentration and δ¹⁵N were found in age sequences of foliage. N concentration decreased with age and δ¹⁵N increased with age. Patterns of δ¹⁵N may be useful in studying nutrient retranslocation within the canopy because, as far as it is known, they are unaffected by contemporary changes in other leaf components. No evidence for increased efficiency of N recycling in spruce from mixed stands as compared to spruce from pure stands was found. The δ¹⁵N data appear to confirm that the amount of N retranslocated depends on the N concentration of the foliage. There was evidence that in a young site the δ¹⁵N value of externally available N in the mixed stands became increasingly enriched over time, while the δ¹⁵N value of externally available N in the mixed stands at a mature site remained constant. Foliar N concentrations and δ¹⁵N of spruce in mixtures with different nurse species and in different ratios were measured. The δ¹⁵N values of nurse foliage differed significantly between species, but no significant effects of nurse species on δ¹⁵N value of the spruce were found. Increasing the proportion of the nurse in a stand increased the foliar N concentration of spruce and caused an enrichment in the ¹⁵N abundance. Soils from one site were subjected to a series of extractions to extract N pools of different liability. N concentrations of 4 pools were measured and δ¹⁵Nvalues calculated. Total soil N in mixed stands was enriched in δ¹⁵N relative to pure stands. It was not possible to identify the pools available to spruce in pure and mixed stands because of large errors in δ¹⁵N values. Organic N pools were consistently enriched relative to largely inorganic N pools. The foliar δ¹⁵N values of spruce in pure stands were close to those of the hot K₂SO₄ extractable pool containing microbial N and amino acids, whereas in the mixed stands, the foliar δ¹⁵N values of both spruce and pine were close to those of the hot HCI extractable pool containing less labile organic N. The results are discussed in relation to the mixtures effect. It is concluded that patterns of ¹⁵N natural abundance in pure and mixed stands of spruce support the hypothesis that in mixtures, spruce has access to a source of organic N not normally available to it in pure stands.

The study analyses the evolution of Joint Forest Management (JFM) in India. The influence of historical, social, economic and cultural factors on participation in JFM is discussed with reference to the Northwest Himalayas. The history of forest use and management in the eras of Pre-British rule, British rule and post-independent period is discussed. The household level differences in six case study level village, with regard to size of landholding, livestock and trees are compared. The influence of family size, caste, literacy and occupation for its dependence on forests for timber, fuelwood, fodder, livestock grazing and non-wood forest products is analysed for implications for participation in JFM. Variation between villages due to altitude, distance from markets, socio-economic characteristics of households all influence dependence on forests. The opinions of households in villages with regard to decrease in forest and forest resources, in relation to forest management option vary. The protection and management of forest areas need to be clearly defined in relation to multiple use rights of many villages. The existence of institutions of co-operative labour, local village gods, women and youth groups and of sacred forest groves provide examples of potential co-operative development for increasing mutual understanding between communities. These can be utilised for formation of rules for forest use and forest management by Village Forest Development Committees. Forest staff have different perspectives with regard to implementation of JFM. They recognise a need for re-training of front-line forest functionaries particularly 'Forest Guards'. Social, economic and political complexities necessitate that JFM must be a process where these factors are incorporated into Forest Department activities and monitored in order to evolve effective institutions for forest use and management. The new forest policy has to be flexible and needs to be amended on the basis of efforts at implementing JFM.

On poor peats and heathlands, satisfactory growth of Sitka spruce (<i>Picea sitchensis</i>), planted pure, can only be achieved with repeated applications of nitrogen fertilizer. However, when spruce is planted in mixture with Scots pine (<i>Pinus sylvestris</i>), Lodgepole pine (<i>P.contorta</i>), or Japanese larch (<i>Larix kaempferi</i>) it shows improved nitrogen nutrition and better growth than pure spruce. The mechanism by which the 'extra' nitrogen required to sustain improved spruce growth has not yet been elucidated. A mechanism is proposed in this thesis. The mycorrhizal community is examined in pure and mixed stands at Culloden Scotland, by recording potential mycorrhizal fruiting bodies, carrying out a seedling bioassay and characterising the mycorrhizal communities on both pine and spruce roots. Approximately 30% of the mycorrhizas on pine mixtures were formed by <i>Suillus</i> spp. but there were no <i>Suillus</i> mycorrhizas on spruce, even in mixture. In pure stands spruce mycorrhizas were mostly <i>Tylospora fibrillosa</i> (55%) or Russulaceae type (16%). In mixed stands, beneath pine canopy, the production of <i>T.fibrillosa</i> on spruce roots was lower (26%) and that of Russulaceae was higher (48%). The Sitka spruce mycorrhizal populations on younger trees in experiments at Speymouth and Shin were also examined. The results suggested that a change in mycorrhizal associations are a part of the 'mixtures effect' and that it starts before closed canopy is established. The ability of various ectomycorrhizal fungi were screened for their ability to break down and utilize protein. <i>Suillus variegatus</i> had the greatest proteinase activity whilst <i>Lactarius rufus</i>, a member of Russulaceae had little ability. The ability of <i>L.rufus</i> and <i>T.fibrillosa</i> to utilise protein hydrolysed by <i>S.variegatus</i> and a <i>Calluna</i> endophyte was examined, both isolates could utilise the filtrates as the only nitrogen source. It is suggested that in mixtures the proteolytic activity of ectomycorrhizal fungi of pine results in an extracellular pool of nitrogen for which the mycorrhizal flora of spruce compete.

Effects of N supply, water stress and the water and nitrogen interaction on assimilate partitioning in <I>Populus</I> 'Balsam Spire' hybrid (<I>Populus balsamefera var</I>. <I>Muchuxii </I>(Henery) X <I>Populus trichocarpa </I>var. <I>Hastata </I>(Dode) Farwell.) were studied through three greenhouse experiments. The seedlings in the first experiment received either 1 or 3 or 9 mol N m^-3 over almost a whole growing season. Growth of the different parts of trees increased markedly by N supply. N supply increased whole tree photosynthesis through increasing total leaf area and decreased photosynthetic nitrogen use efficiency. Total respiration also increased with increasing N supply as a result of increasing leaf respiration and below-ground respiration. Below-ground respiration as a proportion of total respiration, however, decreased with increasing N supply. Nitrogen and carbon content and concentrations in different tree components and in the whole tree increased with increasing N supply. Partitioning of nitrogen into different parts of tree, however, showed no response to N supply. The proportion of carbon allocated to the leaves increased while that allocated to the roots decreased as a result of increasing N supply through increasing the concentrations of structural carbon compounds at the expense of those of non-structural carbon compounds. The ratio of total non-structural to total structural carbon compounds, therefore, increased with increasing N supply. In the second experiment, three treatments were applied to trees in the second half of their growing season by withholding irrigation either suddenly or gradually.