Hi Booli,
Regarding Paper Pulp, and the amount of wood used, it's not so much about the amount of wood used, but rather the types of trees being harvested.
Paper pulp is made from trees that grow quite rapidly, and grow reasonably easily in various conditions (and honestly the timber is not really good for much else), in other words they are not vulnerable to decline or even disappearance, but can be grown and harvested in plantations in many places, and natural areas where such trees grow will remain relatively and minimally unaffected by the process.
Because Trees aren't just Trees, they are a habitat and a major part of environment in a diverse ecosystem, varying in many ways throughout different areas in the world.
For example, here in Australia, we have a big country, we have lots of biodiversity, but that also means we have many many unique types of flora and fauna that sometimes only exists in small communities, sometimes very small communities, and a single species can easily be wiped out completely in a very short time in those cases, and all it takes is the simple destruction of a relatively small area to cause extinction, and when I say destruction I don't necessarily refer to total destruction, although that can be the case, I mean simply the radical change or even the removal of a single important species can become detrimental, cause and effect, I'm sure you'd understand.
We have seen extinction of many species in the last hundred years alone, and it's ongoing, a constant struggle against those who don't know better and don't care to know better, because money talks, and some people consider money is more important than life itself, as long as it's not their own life, I'm quite sure we all know someone like that, it is commonly referred to as Ignorance, Greed, Selfishness, Megalomania, etc.
Even now, with many animals and plants under further threat it' still very difficult to get some people to understand it or to respect it, and we have ongoing issues regarding beautiful unique areas in which certain animals and plants remain, yet may not be found anywhere else in the country, let alone in the world. Once they are gone, they're gone for ever.
Some trees are slow to grow, only grow in certain areas, or propagate only under very specific conditions.
Some Trees can be grown in plantations for commercial purpose, some can't. So choosing the types (Genus/species) of trees is an important factor.
I don't think HPL will take over from Timbers in the musical instrument industry, but it is a viable alternative, and as such can be a contributing factor in the area of habitat and environment matters.
I think until we have a world where every people understands and respects the environment and habitats, there is a need to stay on the ball and keep moving. In one moment the guard drops, and in the next moment people are moving in with industrial machinery and quickly and recklessly taking everything they can and leaving everything else for dead.
That's the reality. It may seem somewhat radical, but the age of technology and machinery is radical. There's been extinction caused prior to this age of Tech Industry, so imagine how it could be now without measures taken to counter it.
It is a problem in the world, it can be very clearly seen in the Amazon to name a more famous case, it can be seen in many countries, in many areas, in many ways.
I sincerely hope this helps with some better understanding ...
As for these Enya X1 series, I think they look like a good well made instrument, and from this review I think they would be a good Ukulele. The Kaka Mahogany Laminate Tenor I bought some time ago was good, and so I think that Enya would certainly pass the grade, so to speak.
I've seen the Concert and Tenor versions of the X1 available on eBay, and they're probably available on some other platforms also.
I was doing some online research on the Kaka around 6 months ago and found an article regarding the Enya HPL models and had a read, it was interesting, I'd never heard of it previously.
Regarding the volume, I am thinking with a Tilt Neck it may be possible to raise the Saddle a touch and tilt the Neck accordingly (to retain good action), to raise the string height above the body, to a relatively reasonable extent which realistically may not be much, and in so doing the volume may be slightly increased, though it may also be a compromise between volume and Tone in that case. I don't know whether or not this is actually the case, but it's a consideration that I think is worth suggestion, if it seems important enough to someone personally.