DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 13/2005 str. 238 <-- 238 --> PDF |
P. Jaloviar: FINE ROOT DISTRIBUTION IN A PURE NORWAY SPRUCE POLE-STAGE STAND Šumarski list - SUPLHMENT (2005), 229-237 on loam and sandy soils, states for sandy soils the biomass of 5,650 kg/ha. For the loam soils he states the value 359 g/m2, what presents 3,590 kg/ha in the top 20 cm of soil. Kodri k (1998) found out 430 respectively 230 g of fine root biomass on 1 m on two plots with different immission impact in the region of Moravskosliezskc Beskydy, what constitutes 4,300 respectively 2,300 kg/ha, he investigated the layer with depth of 30 cm. The necromass weight was 175 g/m2 on the plot under immission impact. The average fine root density varies about 3,000 kg/ha in mature coniferous stands in central European conditions. Kodri k (1997) also states the value of constant biomass (dry mass) of roots with diameter under 5 mm only 1,300 kg/ha for the primeval forest in Biosphere Reserve Pol´ana. Surov y (2000) gives 4,525 kg of fine roots on 1 ha for a spruce shelterwood forest (mature stand together with second layer of next generation). The relation between the soil depth and vital fine root biomass was tested using the method of linear correlation. The comparison of particular spa The fine root density is given in mg of fine roots in 100 ml of fine soil. The advantage of this parameter is its independence from the thickness of investigated layer. At first the fine root density from 7 plots was Vital f The overview about the coefficients of regression lines for all spacings is given in Table 4. From Table 4 results that all absolute and regression coefficients, which are determinant for the shape of particular relation, are statistically high significant different from zero. By testing of diffcrencies between the regression coefficients (t-test) a high significant difference of the b-coefficient from the plot B was found. The differencics in the incline of the lines reflect the various distribution of the fine root biomass. The explanation for this can be that by wider and more asymmetric spacings with low initial plant number (2,500 ha"´) e.g. by the spacing 5.0 x 0.8 m, the available stand space for the crown development is not used as good as by the other more symmetric spacings. This spacing is the only one at present, where the crowns of trees don´t touch in the inter-row space. Therefore the biomass distribution corresponds more or less to the way how the roots take the soil profile in the stands with low stand density, where the competition of neighbour trees is less than in the stands with full density. In symmetric spacings the available stand space is fully used and the competition in the crown layer is much stronger than in the previous case. The proof of it is the visible more intensive drying in the lower parts of the crowns in these spacings and therefore the gradual reduction of the crown capacity compared to the spacing 5.0 x 0.8 m. igs according to fine root density analysed as a whole i.e. the relation between the avera ge concentration and the soil depth was quantified. The comparison was conducted using the method of linear correlation. i roots Despite the significant diffcrencies from zero the regression coefficients of the lines from other plots differ not significant from each other. The correlations between the soil depth and fine root concentration is quite weak, the strongest is on the plot A (5.0 H 0.8) and F (2.5 H 0.8 m), while the computed line explains 69 % respectively 62 % of the variability. Dead fine roots Also in this case the method of linear correlation was used for the comparison of relation between the fine root concentration and the soil depth. The results are shown in the Table 5. The strength of the correlations is more variable at dead roots than vital roots. From previous experiences the state is known, when the dead fine roots shows substantially higher variability and often nearly no relation to the soil depth. On the plots with higher initial plant number on 1 ha the decrease of biomass concentration as well as total fine rhizomass with the soil depth is less strong than on the plots with less dense spacings. The more expected result will be that at higher density and symmetric spacing the fine root concentration will be more homogenous what will be confirmed by less marked depth gradients. We can assume that compared with the summertime the soil moisture was already higher at the beginning of autumn growth of fine roots optionally in the time of their harvesting. On the plots with more dense spacings surely the interception is higher and soil layers under 20 cm were obvious more dry in the time of the harvesting than on the plots with less dense spacings with lower canopy degree. Therefore we can presume on the plots with dense spacing also the root growth was limited only on the soil horizon A in the time of harvesting i.e. on the layers in the depth 0-20 cm. |