Why scarify? Yearly scarified area in Sweden Source: Swedish official statistics

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1 Dept. of Forest and Wood Technology ha 97 Yearly scarified area in Sweden Source: Swedish official statistics 98 Others Private Total Year Scarified, % of clearcut area: Planting 9 %; Natural reg. 69 % Methods: Patch 6 %, Disc trench %, Mound % 99 Ideas: Vegetation Soil physics Mineral nutrients Pine weevil Methods: Patch/Disc tr. Mound Mound, inverted Fill soil Vegetation Scientists: Bärring et al Nutrients or soil physics? Soil physics Nutrients Vegetation pine weevil Nutrients (pine weevil) Pine weevil soil physics Söderström, et al (nutrients) Lundmark, et al Örlander, et al Nilsson, et al Why scarify? Improve microsite for germination of seeds and establishment of seedlings Reduce the risk for damage Improve environment for the young seeedlings

2 Demand on a good planting spot (Söderström, end of 97-ies) Competition between planted Norway spruce and grass vegetation Deschampsia flexuosa Increased soil temperature The root system is surrounded by loose and oxygen rich mineral soil Local drainage The seedling is planted on a mound Seedling volume growth effect of vegetation control treatments (old clearcuts) Effects of irrigation, herbicide and fertilisation. Grass type, southern Sweden, Norway spruce, (Nilsson and Örlander 3) (Nilsson & Örlander 999) 6 Mown Mound Herbicide 3 Seedling dry weight (g) Stem volume (dm3) 3 Yeras after planting 6 8 Not irrigated Irrigated Fertilzed Herbicide Herb+Fert

3 Conclusions from vegetation studies e.g. Nilsson & Örlander 999, Nilsson & Örlander 3 Large pine weevil (Hylobius abietis) Seedlings are subjected to water stress after planting, because of the transplanting shock, the period varies in length dependending i.e. seedling quality Competing vegetation reduce seedling growth during the first two years after planting, whereas established seedlings are little affected by competition from grass vegetation Mowing of vegetation has no positive effect to reduce competition, thus competition is below ground Irrigation has little effect on seedling growth, thus competition for water between planted seedlings and ground vegetation is probably of minor importance for seedling growth Nutrient availability is important for seedling growth, however, fertilisation increases growth only when combined with vegetation control. The ground vegetation is more efficient in taking up applied fertilisers than newly planted Norway spruce Mechanical scarification (even in south Sweden) is sufficient on most forest land to reduce competition for vegetation Scarification reduced pine weevil feeding independent of the age of the clearcut. The relative effect was best on fresh clearcuts. Norway spruce seedlings were planted on - year old clear-cuts. Mortality was measured 3 years after planting. (Örlander and Nilsson, 999) Mineral soil reduced damage by pine weevil more than humusmixtures and cultivated humus. Effect of soil type close to seedling on pine weevil damage. (Petersson et al. ) Mortality, % 8 6 Mound Mortality, % 8 6 Year 3 Year Year Fresh 3 Untreated soil Cultivated humus Hum/min. soil mix Mineral soil Age of clearcut at planting, years

4 Debarked stem area, cm 3 Effect of distance seedling -humus edge on pine weevil damage. (Nordlander et al. ) Untreated humus Mineral soil - Distance from humus edge, cm Planting on mounds reduced pine weevil damage whereas planting in depressions incresed. Planting in mineral soil, debarked stem area. (Nordlander et al. ).3 cm.6 cm. cm Debarked stem area, % Fresh scarification protects better than old. Effect of ageing of scarification patches on pine weevil damage. Feeding was measured on Norway spruce seedlings one and two years after planting. (Örlander and Nilsson, 999) Scarification Mortality, % 8 6 Vegetation and pine weevil Vegetation control had no effect on pine weevil damage if the seedlings were planted without scarification. Norway spruce seedlings planted without scarification on - year old clearcuts. Mortality was measured 3 years after planting. (Örlander and Nilsson 999) Herbicide Year Year Fresh 3 Age of clearcut at planting, years

5 Vegetation cover, % Scarification and vegetation Planting in vegetation free mineral soil patches reduced pine weevil damage. Planting was performed in May 999. The debarked area was measured month after planting.. (Örlander and Nordlander, 3) May 998 Aug. 998 May 999 May 998 +herbicide Debarked area, cm 6 3 May 998 Aug. 998 May 999 May 998 +herbicide Practical implications, pine weevil Planting should be done in mineral soil, humus in any form (mix, pieces, etc) reduces the protection effect Planting spot should be at least cm from humus edge Planting spot should preferably be at or above surrounding soil surface Planting should be done as soon as possible after scarification Scarification methods leading to slower establishment of vegetation than patch scarification, e.g. mounding or inverting, should be preferred Vegetation in the vicinity of seedlings (even outside the scarified patch) increases damage. gave quicker establishment and higher production than other studied methods Kulbäcksliden, N. Sweden Örlander et al 988 a=.-. m Mound Plouging Mounding Disc trenching Not scarified b=.7 m a b Inverted mean volume, ten years after planting, dm3 6 3 Lodgepole pine Norway spruce

6 6 3 gave higher survival and growth compared to mounding in experiments from south to north in Sweden (7 N 6 N (Hallsby and Örlander 3) Height growth, cm Mounding 3 Growing seasons after planting years a a b 8 6 Survival, year, % Mounding Mortality, % 8 6 Untreat. Disctrench decreased pine weevil damage more than other scarification methods. Norway spruce seedlings were planted on fresh clear-cuts. (Petersson and Örlander, ) Untreat. Disctrench Insecticide Year 3 Year Year in relation to other scarification methods - what is the problem? Thawing was faster, the spring of the roots started 3 weeks earlier than in unscarified soil Soil temperature increased more effective into deeper soil layers Less risk for drought compared to mounding and plouging Faster release and uptake of nutrients (N) Effective protection to pine weevil Less vegetation competition Less disturbed humus layer (at least in theory) Less disturbed contour N, mg/planta N- uptake Year Year Year Year 3 Patch Nordborg et al 3 Growth Weight, Year Year Year 3 mg Patch can today only be made with excavator High cost, 3- SEK/ha Technical development has now started ( years after the first experiment were established!)

7 The Asa- capping, more fun than a realistic solution? Mulching - a possible soil treatment method for Nordic conditions? Experiment with patch size, Asa, planted, measured Mulching with wood chips (from slash) x x x Stem volume (dm3 tree-) Leading shoot, cm 3 Stem volume nine years after planting 6x6 Size, dm Survival % 8 6 cm 8 6 cm cm Mulch detph (cm) Kontroll x x x Johansson et al (manuscript) Mulching improved soil moisture conditions Improved nutriend availability Improved growth during a ten year period reduced the amount of competing vegetation did not affect survival or damages by pine weevil 6x6 Size, dm The size of the seedling should be adapted to scarification and protection of the seedling The pine weevil model The storm Gudrun felled 7 million m3 the 8 jan. Probability of mortality caused by pine weevil Nilsson, Petersson and Örlander in prep " # Kontrakterad medelvolym, m3fub/ha medlemsareal. Uppdelat på församlingar Scarification after the storm Gudrun Ca. ha clear-cut Increased problems with pine weevil Increased competition because of longer delay before planting Scarification important $! % & % '& Data saknas Scarification in storm felled areas is a challenge!

8 Longterm productivity and mechanical scarification Is long term productivity negatively affected by scarification? Long term Swedish experiments (up to 7 years age) on dry poor sites show that production was not negatively affected by mechanical scarification (Örlander et al 996) The results are supported by experiments e.g. in Germany and Great Britain. Is it possible to increase long term productivity using scarification? 8 Mean heght, cm 6 experiment, Northern Sweden (Kulbäcksliden) Disc trenching Not scarified Site index 3 Age, years G3 G8 G G G6 per cent 8 6 Survival, years after planting Disc trenching Not scarified Demand on a good planting spot (Söderström, end of 97-ies) Demand on a good planting spot (Söderström, end of 97-ies), Updated 6 Increased soil temperature The root system is surrounded by loose and oxygen rich mineral soil Local drainage The seedling is planted on a mound Increased soil temperature The root system is surrounded by loose and oxygen rich mineral soil. Planting should be done at least cm from humus edge. Local drainage The seedling is planted on a mound or in the level of surrounding soil. The seedling is planted close to inverted humus to achieve nutrient supply The seedlings are normally planted - cm deeper than they were in the nursery. Type of seedling, etc. should be adapted after scarification method. Planting should be made when the scarification is fresh, preferably on young clearcuts to reduce vegetation problems.