Dear Stefan,
Thank you for your question. To get more information on elementary exchanges, you can have a look at the exchange properties. By logging in to ecoQuery (https://www.ecoinvent.org/login-databases.html, creation of a free guest account is mandatory), you can look for the process where you encountered those exchanges and navigate to the ‘Exchange Properties’ section. Ecoinvent offers two properties considering mass, dry and wet mass (definitions in the glossary, https://www.ecoinvent.org/support/glossary/glossary-detail.html?&l=d).
For the exchanges you asked for, the masses are (equals one cubic meter):
Dry mass [kg]
Wet mass [kg]
Gas, natural, in ground
0.8
0.8
Wood, unspecified, standing
550
632.5
Gas, mine, off-gass, process, coal mining
0.8
0.8
Wood, hard, standing
650
747.5
Wood, soft, standing
461.4
784.3
I hope this answers your question. Feel free to contact me if you have more questions, otherwise I wish you a nice festive season and a Happy New Year.
Kind Regards,
Daria Dellenbach, Junior Data Analyst, ecoinvent association