In different harvesting seasons, the lignin, holocellulose and pentosan contents in bamboos didn''t change too much.

至于同为化学主分的木质素、全纤维素、聚戊醣等分，则没有节变化。

That means the birch from high longitude and latitude areas will have lower content of the ash, extraction and lignin, higher content of the holocellulose and pentosan in the wood.

这表明，选择较高经纬度地区的白桦，低灰分、抽出物、木素含量，提高综纤维素和聚戊糖含量。