You should just need to up their frequency to 100, though when i think about it, the biome is subterranean_water, like plump helmets etc. so that would mean you probably can't find it above ground, I would reccomend expanding the biome token so it can grow in more environments than just underground so you can find it above ground too, though id just reccomend
[BIOME:ALL_MAIN]
that would result in it being everywhere so you should be able to find it, up the frequency to 100 so the herbalist should find it alot and bang, the dwarven scientists who made it would be proud, though upset due to less sales they will be getting *got the biome token from the wiki by the way, dont know myself if it works, but the wiki is reliable*
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i havent looked into making new kinds of wood or in much detail about trees, though i did search what you said there on the forum and got this post
http://www.bay12games.com/forum/index.php?topic=27322.msg331592#msg331592 i would say if that works you just substitute the metal you want into the reaction and generate a new world so the reaction is enabled and you would be good to go for making logs of a certain metal *thanks go to poster from said thread*, for new kinds of wood entirely the wood tokens from the matgloss_wood look like a different kettle of fish i would read more about it from the wiki before id go into any modding with them
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on another note, the silk reaction for some reason has an identity issue making it think its the aluminium reaction, i think its just that as i just tested the adamantine thread and it reacts ok *had to use cheat-o-matic to get 1800 points in embark screen for it XP*
ill post the current versions of the silk plant and silk reaction in case im overlooking something so someone could save the day XP, though given the silk plant thread appears ok *whose value ill be adjusting soon so it isnt free on the embark screen* the plant isnt the problem, i think its the reaction, but i cant explain the identity issue, i even went to a vanilla DF to test it again and it repeated again (i use civillisation forge mod and a few others which add more reactions so i dont think its anything to do with too many reactions)
edit: figured out the identity issue, there was a spelling mistake in the aluminium crop plant raw so im going to correct it, also the silk reaction just plain doesnt work XP
[REACTION:SILK_PLANT_THREAD_TO_SILK]
[NAME:Silk plant thread to silk cloth]
[REAGENT:1:THREAD:NO_SUBTYPE:PLANT:SILK_PLANT]
[PRODUCT:100:1:CLOTH:NO_SUBTYPE:SILK:SPIDER_CAVE]
[MATGLOSS_PLANT:SILK_PLANT]
[TILE:6]
[COLOUR:7:5:1]
[NAME:Silk plant][NAME_PLURAL:Silk fields]
[GROWDUR:2016][VALUE:0]
[THREAD]
[SEEDNAME:Silk seed][SEED:2:2:1]
[GENPOWER:1]
[SPRING][SUMMER][AUTUMN][WINTER]
[FREQUENCY:0]
[CLUSTERSIZE:5]
[WET][DRY][BIOME:SUBTERRANEAN_WATER]