PiGraham wrote: richrarobi wrote:
I know a local council (Bracknell) where residents have to pay for collection of their "green" waste, and the "collectors" just bung it into the (land-fill or for burning) ordinary collection truck.
I'm not surprised you give no reference for that claim. In this era of fake news it's important to check and give sources, if you have them, and be responsible by not posting reactionary gossip if you don't have reliable sources.
In this case there may be no evidence to give. I can't find anything online. Even if this was fake news I would expect to find something; if there was a real story there I would have expected some media to have picked it up. Maybe it is more likely that the council are using the same compactor lorries for both jobs and this has been noticed by residents who jump to the wrong conclusions.
Whether wood is carbon negative might be over-stating, but it is certainly very low foot-print. The wood itself is carbon neutral but there is some carbon required to process it (and drive the laser). It is far and away a lower footprint than using new plastic.
There's a fascinating book I have about sustainability called "Time to Eat The Dog?" and it makes some interesting calculations. For example it consumes less carbon for four people to commute to work in one car if they power themselves with locally grown potatoes than it would be for them to cycle to work, take a shower there and power themselves with imported beef-burgers.
Wood has no effect on carbon if it grows, dies and decays. Any work done on it will emit carbon. However if one was to grow a tree organically with minimal, locally sourced supplies, chop it down by hand using no more calories than one would ordinarily consume, prepare and season it by hand likewise and use it for projects using only hand-tools and no metal or synthetic fixings, then that should be carbon neutral. If one were to convert all the waste to charcoal and bury that deeply, I imagine one might produce a negative carbon foot-print.
There are two issues here of course: sustainability and carbon foot-print. They are not the same although they are both worthwhile issues and meet in oil, gas and coal. A wooden case is clearly sustainable --- trees can be grown any time one wants -- and it has a low but non-zero carbon footprint. Plastic is not sustainable and has a high footprint. However anything saved from landfill for a new life as a Pi case has a carbon footprint even lower than (new) wood no mattter what it is made of and its sustainability is not an issue.
Reduce, Reuse, Recycle, in that order.