Paarlahti, Kimmo

Jukuri

METSÄNTUTKIMUSLAITOKSEN SUOTUTKIMUSOSASTON  TIEDONANTOJA  5/1972  JAAKKOINSUO EXPERIMENTAL  AREA  Kimmo Paarlahti Helsinki  1972 Jaakkoinsuo  Experimental  Area After the Finnish  National Board  of Forestry had started  systematic  ditching activity for the utilization of  peatlands for forestry purposes,  it established  in 1909 the Jaakkoinsuo  Experi  mental Area in order- to clarify  the principles  of forest drainage.  The primary  aim was to find  out by means of experiments,  how large  a yield of wood can be achieved  on sites with different nutrient contents and, further, how various drainage efficiencies and stand treatments affect the yield. The first ditchings at Jaakkoinsuo  were carried out in 1909 and, since then, they have been extended  for various  projects. In 1923, the Jaakkoinsuo  Experimental  Area  was placed under the Finnish  Forest  Research  Institute, the activi  ties of which commenced in 1918. Jaakkoinsuo  Experimental  Area measuring  97.5 hectares  is  located  at 62°04' N, 24°34'  E. The  mean  altitude is 120 m above  sea level. The bedrock  of the area is largely composed  of acid plutonic rocks  and the minerogenic  deposits are composed  of Glaci  fluvial  Drift. The thickness  of the peat  layer  in the swamp-area  ranges from 0.3 to 3.5 m. Mean values of some climatic factors:  -  Mean annual  temperature 3.4° C - Mean temperature  in July ' 16.8° C -  Mean temperature  in February « 8.4° C  '  -  Sum of  daily mean  temperatures  (>+ 5° C)  during the growing season 1220.0° C -  Average duration of  growing  season  (>  +s° C) 164 days  -  Annual precipitation 600 mm The first experiments for determining tree growth^after drainage were  established  as  early  as 1909 and  further experiments  have  been  established  more recently.  In  addition, the following  experiments  have  been  established  at Jaakkoinsuo:  in 1926, experi  ments in which mineral soil  was applied, in  1929 liming experi-  -  merits and in  1957 ash fertilization experiments.  Fertilization 2  experiments  using  common  fertilizers were  started in 1949. Strip  width experiments as well as ecological  experimental  fields are also to be found in this area. The excursion  route begins  at the part  of  the swamp  poorest  in nutrients. In general,  the fertility improves  throughout  the  course of the excursion  route. 1. Sinking  of the peat surface  after drainage  There  are several series  of poles at Jaakkoinsuo,  which  reach  down  to the  mineral  soil. The  height  of the poles  is adjusted by  levelling. It is possible  to find out by means  of  the pole  series,  how much  the peat layers of  different thicknesses  have sunk  as  a result of drainage.  2. Ecological  experiments in peatland forests  Here at Jaakkoinsuo  as  well as  in the experimental  area of Kivalo  in Northern Finland  close to the arctic circle,  there are ecological  experiments  on a pine swamp  and  a spruce-birch  swamp. The effect of the growth factors of trees and  the differences in  the degree of efficiency  induced  artificially  in these  factors  on  the total growth and  the annual rhythm of growth  has been  studied  in these experimental fields since  1960. The following growth factors  have  formed the primary  objects of the research:  ground  water conditions,  soil temperature,  nutrient state of the ground,  air temperature and air humidity. All these factors have been  regulated artificially. The ground water relations  have  been  changed  by regulating  the drainage depth at 0, 10, 30, 50, and 70 cm from the ground surface  on various  plots. The  ground temperature  has been  lowered  by removing the snow  from the plots throughout  the winter,  causing the ground  to become  deeply  frozen. In  spring, the snow has been  spread back  over the frozen  ground and  covered  with straw, in order  to prevent  the snow and frozen  ground from thawing. It has been  possible to keep the ground temperature at a higher than  normal level by covering  the soil with straw before the winter, thus  3 retarding  freezing of the soil. The nutrient state of the ground has been regulated by means  of various fertilizers. The air tem  perature  has been  raised  by building plastic shelters  around  the  sample trees and, further, by heating the shelters.  The  diameter growth has been measured  on the sample  plots at intervals  of 2-3 days by a banding method developed for these  investigations.  The height growth has also been  measured. Further  investigations  have  been  made  into the biological  activity  in the  ground and the  depth distribution  of  tree* roots.  The results of the fertilized plots show (Appendix  2) that the greatest  difference in tree growth is found  between  the plot of 0 cm and the plot  of 10 cm. Concerning  the depths of 10, 30,  50, and 70  cm there are no significant differences in the growth. A clear positive correlation  can  be found  between  the  drainage depth and tree growth on the unfertilized Sphagnum peat poor  in nutrients. The growth is clearly  the best on the sample  plot where  the drainage depth  is 70 cm. In the peat  soil very poor  in nutrients the biological activity and the mobilization  of scarce nutrient resources  are most effective on the sample plot  where the drainage depth  is 70 cm. ; It is worth noting that the straw layer  used in soil tem  perature  experiments  has improved  the tree growth by eliminating the uptake of  nutrients by the ground vegetation and  by keeping  the surface  layer  humid  enough for the decomposition and  mobiliza  tion  activities  of the soil microbes.  (Appendices 2, 3,  and  4). The results of the experiments on temperature conditions  show,  among other things, that the time when  growth commences  is independent of the prevailing soil temperature and is determined  solely  by the increase  in the temperature  of  "the surrounding  air in spring. Thus,  on the plots where the soil  has been  covered  by  snow and the ground around  the root systems has been entirely  frozen, the growth starts at the same time as on the normal con  trol  plots. Similar results  have  been  obtained  from experiments  in plastic  shelters. .  4 3. Production  experiments (with different stand  treatments) The object of the experiment  is to find out,  how the various  stand  treatments affect the total yield and  the growth of the tree stand. The experiment  consists  of three  experimental  plots. Plot  5a  has been  kept  in  an  unthinned  natural state. On plot s'c  the  stand has had  light thinning treatments and  on plot  5b  heavy  treat  ments. This explains  why there is at present  a naturally  regene  rated spruce  stand on  the plot.sb.This stand  forms the second  tree generation after drainage. The information given in Appendix 1 indicates  that the largest  total yield has been achieved  on the plot which  had no thinning treatments (sa). Technically,  however, the stand is  of very poor quality and  so far, the cuttings have not produced any income. On the plots  which  had  thinning treatments the stands  are of good quality and  several cut.tings  have produced  income.-'  " - 4. Production  experiment (with different stand treatments)  The experiment consists  of four  experimental  plots. Plots 7b and 8b have been kept in an unthinned  natural state. On plots  7a and  Sa  the stands  have had regular  light  thinnings. In this  case, too, the information given in Appendix  1 indicates  that the  total yield of the unthinned  plots (7b  and 3b) has been  larger  than that of,the plots  which had thinning treatments. 5. Production  experiment  The object of the experiment.is  to study  the natural re  forestation  and the total yield  of  tree stands.  At the time of ditching (in 1909) there were  some small birches  and willows growing in the area. After  drainage a natural birch stand  appeared in the area. Because the birch stand  has had  regular  thinning treatments, a natural spruce  stand has appeared in the under story. The last  of the birches were  cut in 1958. Technically,  the spruce  stand  growing at present  in the area is of very good quality. 5 The stand increment  as well as  the total yield of  the area are very large as can be seen  in Appendix 1. 6. Reforestation  experiment  using  controlled  burning  The object of the experiment  is to study, how controlled  burning  may be applied in the reforestation  of peatlands. The  pine stand  originally on the site was cut in 1956 and controlled  burning was  carried out in 1958. The  stand  has been naturally  regenerated  with seed  from the surrounding  forests. Because the  dense  birch stand almost suppressed  the pine seedlings,  the stand  of birch  seedlings  has been controlled with a herbicide  application.  7. Production  experiment  The peatland site  type on plot 23a is the most fertile site  at Jaakkoinsuo. At the time of ditching (in 1909) there  were  some  small-sized  pines  of poor growth growing in the area. It can be seen  in Appendix 1, that the total yield after drainage has  been  very  good and  the annual  mean  growth after drainage has been  calculated  to be  7.6 solid  m per hectare. The experiment  shows  that even  a swamp  with a fairly thick peat layer can be made  to produce  very  highly  productive  stands  of large timber trees; 8. Production  experiment  At the  time of ditching, plot 15a was an entirely treeless 3 swamp. However, up to now, it has  produced 248 m of wood and the present  stand  consists  of large timber trees of fairly good quali  ty. The  importance of  the nutrient content of the site for wood  production  after drainage can clearly  be seen  in  Appendix 1. The  total yield and the growth of the stand on plot 23a are-nearly  twice those of plot  15a. Appendix 1xx} 'Sampleplothasbeen establishedin1963'C=sedge(Carex)-rich  PS=PineswampH=Herb-rich  SS•=Spruceswamp P=Fen-likeProductionexperiments HW  Sample  Original  Peat  Site  Tree  standin1972 Total  No.  plot  No.  peatland  sites type  layer,  m quality  index  Birch  Total  Annual  increment  production  U..6)  solidriK./ha  5a CPS  0.4  5 .5 99  l6l  265  4.3 324  3 5b  CPS  0.5  •3 29  29  2.7  ,2S7  5c CPS  o.6 3 76  19 46  141 5-6  -XX)• ?a.  CPS  0.4  .3 80  23  82  185 6.3  291  4 7b' ,CPS  0.4  3 135 24  133  292  CO m 346  8a  CPS  0.4  3 190 7 32  229  '7.5  310 8b  CPS  0.3  3 166  42  74  .282  7.2  316  5 26  HCSS  0.3  2  181 l8l  10.4 412  7' 23a  FPS  1.0 1 200 10 55  265  7.2  '471  8 15a (open)CS 0.8  4 136 32  168 3.5  248 Appendix  2  Development  of the basal  area of tree stand on the Jaakkoin  suo pine swamp experimental  area. Appendix  3 Development  of the basal area of tree stand on the Jaakkoin  suo  pine swamp experimental  area. Appendix  4 Development of  the basal  area of tree stand on the Jaakkoin  suo  pine swamp experimental  area. METSÄNTUTKIMUSLAITOKSEN SUONTUTKIMUSOSASTON  TIEDONANTOJA-sarja  esittelee suontutkimusosaston  (metsänparannuksen  tutkimusosaston) tutkimusten  tulok  sia lähinnä  tutkijoiden keskeistä  informointia ja tulosten  ennakkoon  kri  tisointia varten. Käsikirjoitukset  sarjassa  julkaistavaksi  hyväksyy  osasto  päällikkö. Jokaista julkaisua  on 6 kpl,  joista  1 on  tekijällä,  2 nähtävänä suontutkimusosaston  käsikirjastossa  (Unionink.  40  A, 00170  Helsinki  17),  1 Parkanon, 1 Pyhäkosken  ja 1 Kolarin  tutkimusaseman  kirjastossa.  Sarjassa  on ilmestynyt tähän  mennessä: Huikari,  0. 1972. Metsäntutkimuslaitoksen  suontutkimusosaston  (met  sänparannuksen  tutkimusosaston)  tutkimusohjelman  laadinta  sekä  tutkimus  tehtävät  ja budjettiesitys  vuodelle 1973. MTL mpt.  1/1972. 124 s. Huikari,  0. 1972. H-kulttuuri. MTL mpt. 2/1972. 19 s. Paavilainen,  E. 1972. Lannoitteiden  lentolevityksen  tasaisuu  desta. MTL mpt.  3/1972. 8 s. Veijalainen, H. 1972. Hillasato kesällä  1972 eräillä suontutki  musosaston  koekentillä.  MTL mpt. 4/1972. 38 s.  Paari ahti,  K. 1972. Jaakkoinsuo  Experimental  Area. MTL  mpt. 5/  1972. 9 s. 

Jaakkoinsuo experimental area

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