Relationship between ethanolic extracts of yellow birch and tree characteristics

- Ethanol-soluble extracts were analysed through GC-MS and UV-spectrophotometry.
- The extracts from wood of non-vigorous trees had the highest total phenols content.
- Dying trees bark presented the highest betulin content.
- The largest source of variation in the chemical compounds was at the site level.
- Tree characteristics accounted for a small portion of the variation in compounds.

The traditional wood industry has gone through an important crisis over recent years due to a decline in demand for certain traditional products coupled with a decreased demand due to competing developing economies, among others. In this context, the production of high value-added products and the exploration of new markets could promote the transition to a more resilient forest industry. One of the up and coming markets involves the plant-based extracts, which can be used in several industries, such as pharmaceuticals, cosmetics and nutraceuticals. In order to better understand the potential that biorefining products from yellow birch (Betula alleghaniensis) have to produce high value-added extracts, this study evaluated the relationship between total phenols, major triterpenes and phytosterols content in wood and bark of the studied species and selected tree characteristics. Results showed that the majority of the studied chemical compounds were related to tree health. The wood of non-vigorous trees presented the highest total phenols content among the three vigour classes, with an average of 394.9 ± 138.6 mg GAE g−1 of oven-dry extract, while presenting the lowest β-sitosterol content (3.0 ± 0.9 mg g−1). The bark of moribund trees contained the lowest total phenols content (317.6 ± 46.8 mg GAE g−1), but the highest betulin content (6.6 ± 4.2 mg g−1). Variations in bark compounds were also frequently correlated with the presence of fungal fruiting bodies on the stem, being associated with lower extract values for the betulin, lupeol and lupenone. Tree vigour and the presence of sporocarps in the stem explained a significant part of the variation in the studied chemical compounds from wood and bark. A remaining unexplained variation may be attributed to stand-level conditions.