K U N G L. S K O G S H Ö G ·s K O L A N S S K R I F T E R BULLETIN OF THE ROYAL SCHOOL OF FORESTRY STOCKHOLM, SWEDEN Nr 34 Redaktör: Professor LENNART NORDSTRÖM 1961 Development and yield of Douglas fir (Pseudotsuga taxifolia (Poir.) Britt.) and Sitka spruce (Picea sitchensis (Bong.) Carr.) in southern Seandinavia and on the Pacific Coast By STEN KARLBERG STOCKHOLM 1961 EMIL KIHLSTRöMS TRYCKERI AB Development and yield of Douglas fir (Pseudotsuga taxifolia (Poir.) Britt.) and Sitka spruce (Picea sitchensis (Bong.) Carr.) in southern Seandinavia and on the Pacific Coast AKADEMISK AVHANDLING som med vederbörligt tillstånd av Kungl. skogshögskolans lärarråd för vinnande av skogsvetenskaplig doktorsgrad offentligen försvaras på Skogshögskolan, lärosal III lördagen den ll mars 1961 kl. 10 AV STEN KARLBERG STOCKHOLM 1961 CONTENTS Page Introduction 5 l THE COMPILATION OF YIELD TABLES FOR DOUGLAS FIR AND SITKA SPRUCE . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 7 The collection of data .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 7 The classification of Sitka spruce sites .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 9 The classification of Douglas fir sites .... .... ........ ............ ...... ...... .... 14 Yi eld tables . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 17 A. The number of trees per hectare .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 20 B. The mean basal area diameter .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 23 C. Basal area per hectare . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 24 D. Form-height . .... .. ... .. .. .. .. .. .. .. .. .. ... .... .. .... .. .. ... .. .. .. .. .. .. .. 26 E. Volume per hectare . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 28 F. The mean diameter of the trees removed in thinning ..... .. ... ..... 31 G. The mean height of the trees removedin thinning .... .... .. ...... .... 31 H. The basal area increment .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 32 I. The volume increment ......................................................... 39 J. Total yield . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 40 Yield tables for Douglas fir .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 41 Yield tables for Sitka spruce . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 45 II DOUGLAS FIR GROWTH AND GROWING CONDITIONS .. .. .. .. .. .. .. .. .. 49 Morphology, taxonomy and range .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 49 Douglas fir provenances . .. .. .. .. .. .. .. .. .. .. .. .. 53 Douglas fir growth on the Pacific Coast and in southern Seandinavia 60 Douglas fir growth according to this and other European yield inves- tigations .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 64 The growth and yield performance of Douglas fir in relation to that of Norway spruce . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 69 III SITKA SPRUCE GROWTH AND GROWING CONDITIONS .. .. .. .. .. .. .. 84 Morphology, taxonomy and range .. .. .. .. .. .. .. .... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 84 Sitka spruce provenances . .. .. .. .. .. .. .. .. .. .. .. .. 87 Sitka spruce growth o.n the Pacific Coast and in southern Seandinavia . 89 Sitka spruce growth according to this and other European yield in- vestigations . .. .. .. .. .. .. .. .. .. .. .. .. .. .. 90 The growth and yield performance of Sitka spruce in relation to that of Norway spruce ........................................................................... 94 IV CONCLUSIONS 106 V ENCLOSURES 111 VI LITERATURE CITED . .. .. .. .. .. .. .. .. .. 121 VII ABSTRACT IN SWEDISH .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 130 lntroduction In 1950 and 1951 the growth conditions of Douglas fir (Pseudotsuga taxi­ folia) and Sitka spruce (Picea sitchensis) in their ranges along the Pacific coast of North America were the subject of the author's study. Extensive travelling in the large area provided inclusive information on largely dif­ ferent habitals with respect to elimate and soil. This strenghtened the opin­ ion that, under certain conditions, these two species should succeed in the southern and south-western counties of Sweden, too. Douglas fir, which in north-west America exhibits an impressive growth on many locations within its large range (McArdle 1930, Munger and Morris 1936, Isaac 1949), has also shown promise in Danish experiments ( Opperman 1915, 1922, Fabricius 1926, Holm 1940 etc.). Similar experience has been reporled in Germany by e. g. Kanzow (1937) and Schenck (1939). Later studies published by Hummel and Christie (1953) give accounts of considerable increment in sample plots of Douglas fir and Sitka spruce in Great Britain. Early Danish investigations (Opperman 1923 and Fabricius 1926) also suggesled that in certain cases the yield of Sitka spruce is appreciably greater than that of Norway spruce (Picea Abies) of German origin. The results of several preliminary studies of the development in southern Seandinavia of both these tree species ( Karlberg 1952), and the resulls from sample plot studies in Scotland ( Karlberg 1955) and northern Ger­ many, compare well with the results reportedi in the literature cited. For this reason the author considered it important to attempt an analysis of the value of Douglas fir and Sitka spruce to forestry in the south of Sweden. The analysis may be of particular interest against the background of the research currently being airned at raising the yield by the introduction of Norway spruce from more southerly parts of its range (Germany and Poland) or by the breeding of high-yielding Norway spruce of Swedish origin. In conjunction with the examination of the growth of the two American species in relation to that of Norway spruce, the latter was also subjected to investigation, when stands of these species have been growing side by side in similar conditions. 6 STEN KARLBERG Since the stands of Sitka spruce and Douglas fir in southern Sweden are few and small with incomplete management records, they would be un­ suitable for a comprehensive study of the yield. For this reason the field work was chi.efly undertaken in Denmark, where the elimate is generally similar to that prevailing in southern Sweden. Furthermore, many of the Danish stands are weil known with respect to their early development. Collecting the material, the predominant part of which was obtained between 1951 and 1953 and later supplemented1 the author has received in­ valuable assistance from Dani.sh forest owners and foresters. To all I would like to extend my warmest thanks. The assistance given by the Danish For­ est Experiment Station, the Danish National Forest Survey and The Royal College of Agriculture in Denmark in the form of information and advice is also acknowledged and sincerely appreciated. The author is also indebted to the many specialists of the Forest Research Institute and the Royal School of Forestry in Sweden, with whom I had the privilege of disenss­ ing the work plans. Special gratitude is due Dr John D. Duffield, Nisqually, Wash., and Mr Leo Isaac, Portland, Oreg. for their valuable assistance during the stay in the U .S. The investigation was financed by grants from the Foundation for Forest Research. A grant awarded by the Swedish-American Foundation made possible the studies in U .S.A. ( 1950-1951), which provided a broad basis for evaluating the prospects of growing these two species in Sweden. Grants have also been received from the H. Ax:son Johnson Foundation for visits to Great Britain and Holland to study the development of various strains of Sitka spruce and Douglas fir in these countries. Germany and Norway have also been: visited on the same purpose. I. The compilation of yield tables for Douglas fir and Sitka spruce Since the method of compilation has generally been consistent, the follow­ ing account of the collection and processing of the data is common to both species to keep the presentation concise and avoid repetition. The collection of data a. Occasionally establisbed plots Only stands which have developed practically free from attacks by fungae and insects are included in the study. The sample plots have been estab­ lished in pure stands with a maximum admixture of Norway spruce of 10 per cent. The size of the sample plots has only exceptionally been less than 0,25 hectare. The shape of the sample plots has been adapted to the locality. Regarding the rectangular plots1 Iai.d out by means of a right angle prism, a difference in lenght between the paraHel sides of up to l metre has been accepted. In the case of irregular quadrangles the diagonals have been measured and the area calculated according to the Heron formula. Distances were measured with a steel tape and readings were rounded off to nearest decimeter. All the trees were cross calipered at breast height and the readings rounded off tonearest centimeter. Calipered trees have been clearly marked. All measurements were made in the autumn after the terroination of growth, or in the early spring (cf. Tiren 1929) . Heights were measured with a controHed Blume-Leiss hypsometer on the basis of two readings per sample tree.