Trees do not grow by themselves after world generation in Creativerse. Parchwood trees are part of the recent 4 template worlds that each freshly "generated" game world is a random copy of. Parchwood trees also cannot be grown by players from any tree Saplings.
During daytime, common green Leafies might spawn on Parchwood Leaves as long as no artificial light sources are illuminating these leaves.
After nightfall, Night Leafies are able spawn on Parchwood Leaves - again only if no artifcial light sources are nearby.
During night-times, ordinary Wood Treasure Chests can randomly spawn in dark areas on all types of tree leaves including Parchwood Leaves - except for Corrupted Leaves, on where Diamond Treasure Chests (and Corrupted Creatures) can occasionally spawn during day and night as long as the area is shrouded in complete darkness.
How to obtain
Blocks of Parchwood Leaves can be harvested/pulled with your ArcTek Gauntlet without any Power Cell equipped. Still, it is recommended to use Mining Cells, since the harvest process will be faster and no Power Cell will lose any durability when harvesting uncorrupted Leaves.
It's not possible to multiply Parchwood Leaves by placing them and picking them up again (different to some tree Flowers).
Of course you won't be able to pick up such blocks on game worlds, on player claims or in Adventures where your Permission rank is not sufficient (mainly when you are merely a visitor), which can only be changed by the owner of the game world, the respective claim owner or Adventure creator.
Parchwood Leaves can be bought as parts of (customizable) building kits for any customizable Blueprint with Coins, which in return are purchasable for real money via Steam Wallet in the ingame Store. You can use Blueprints that you have captured yourself with Capture Blocks, as well as Blueprints that were made by other players and that you have subscribed to in the Steam Creativerse workshop, or Blueprints that you have customized with Parchwood Leaves.
To buy a building kit, either select the according Blueprint or activate a cornerstone that has been placed into the game world (and has optionally been customized). Check the content of the block kit first by clicking on the description "Built with xxx Blocks" before you'll click on the green price tag button below "Get kit and build now".
Parchwood Leaves cannot be obtained from any randomly spawning Treasure Chest nor from any Creature (the "golden"-colored Leaves blocks that you can obtain from Autumn Leafies from time to time are Citrus Autumnwood Leaves). Parchwood Leaves are also not part of any seasonal game content, Store bundle, seasonal minigame event reward or NPC trade offer.
How to get rid of tree Leaves
In Creativerse, tree Leaves will not decay / vanish by themselves when you "cut" down the stem of a tree, and it won't help if you remove all the Wood-blocks that the trunks and branches are made of either.
Instead, all tree Leaves (as well as all Flower-blocks, Beeswax, Queen Bees, Vines, Vines-covered Wood blocks and Moss-covered Wood blocks) will prevail and float in the air even as single blocks, until you will take them down manually, destroy them or use Excavators on them.
Basic Excavators can remove up to 7x7x7 uncorrupted Parchwood Leaves blocks at once and save half of these blocks in their (usually 3) loot bags.
Destroying tree Leaves completely is possible by using the AOE Gauntlet Smash attack of your ArcTek Gauntlet when you have at least 75% of your maximum Stamina (either 75 for F2P players or 150 for "Pro" players, or more if you consume Stamina-enhancing Food) - by hitting the Leaves from above (it's a ground smash that will only affect 1 block upwards at most). This will remove Leaves up to 2 blocks to the sides and downwards from the point of impact without leaving anything behind.
Parchwood Leaves require a Stone Mining Cell (or stronger Power Cell) in order to be eradicated. Still, Power Cells don't lose durability when executing the Gauntlet Smash. Wood blocks, Vines, Moss, Queen Bees and Beeswax will not be destroyed by that. All other types of uncorrupted tree Leaves can be destroyed this way even without any Power Cell equipped.
You can alternatively destroy uncorrupted tree Leaves by using TNT, and you can burn Parchwood Leaves to nothingness by throwing Fire Bombs or Flaming Skulls at them. This can burn 7x7x7 blocks of Leaves at max. instantly (usually only 7x7x4 though), but will also remove uncorrupted Wood blocks that the tree trunks are made of, as well as any nearby tree Flowers, Moss and Queen Bees. On the other hand, Vines and Beeswax will not be destroyed, but will prevail, floating in the air.
Be careful: in hot biomes like Savannahs (where Parchwood trees can be found), fire can spread and burn down whole trees. Burning leaves and other flammable materials is only possible on player claims and game worlds where the option "fire spreading/sim" is enabled though.
As long as the fire spreading option of game worlds is enabled (which it is by default), placing torches or any other items with open flames or fiery blocks like Hardened Lava directly under blocks of Parchwood Leaves or uncorrupted Parchwood (of tree stems and branches), can burn the Leaves and Wood blocks to nothingness in hot environments that make a heat meter/scale show up, like Savannahs, Jungles, Oceans or on the Lava layer, but also in much cooler Swamplands.
Placing several torches or heat sources with open flames next to each other can even raise the chances to set flammable materials like Parchwood Leaves on fire. Liquid Lava, Fire Bombs or Flaming Skulls will immediately set Parchwood Leaves blocks on fire.
If Parchwood Leaves blocks and/or Parchwood blocks start burning, the flames are then able to spread to other nearby flammable blocks, even across gaps of 1-2 blocks on game worlds and player claims where the "fire spreading" option is enabled. This way a whole wooden building or forest (especially Parchwood trees, Weepwood trees, Wildwood trees and Shorewood trees) can burn down in the worst case.
Fire cannot be extinguished by using liquids, but it can be stopped from spreading by claiming the area and making sure that the claim (advanced) option "fire sim/spreading enabled" is disabled (by default). Fire Bombs (and Flaming Skulls) will have no effect on these claims either.
It is also possible for owners of the game world (F2P players included) to toggle the spreading of fire on a whole game world in the basic world options ("edit world" and "disable fire spread"), which will also render Fire Bombs and Flaming Skulls useless there. Another option to stop fire from spreading would be to create forest aisles/swaths wide enough so that the flames cannot leap over.
Only Vines-covered Wood blocks, hanging Vines and Beeswax will not burn and such remain intact, while any tree Flowers, Moss and Queen Bees will burn away together with all uncorrupted Wood blocks and tree Leaves.
How to use
Uncorrupted Parchwood Leaves can be placed as solid blocks for decoration and can also be used for building; however they can make Creatures spawn on them, mainly Leafies during the day, and Night Leafies in darkness.
You can fully rotate Parchwood Leaves into all directions by pointing your cursor at them, then pressing and holding R (as the default key) and then moving the mouse while holding down the left mouse button. The chosen rotation angle can be "locked" too by simply typing "r" while looking at an already rotated block or item, so that all blocks of the same stack in the chosen quickslot will then face the same direction when being placed.
One block of Parchwood Leaves can be cut into 4 blocks of Shredded Leaves in a Processor at a time. No crafting recipe is required for this. Simply carry blocks of Parchwood Leaves with you in your inventory and activate a Processor in the game world with right-click or "f" (as the default key) while pointing your cursor at the Processor.
Shredded Leaves can be used as building blocks, but be careful: Shredded Leaves are just as flammable as fresh leaves when being placed. You can process Shredded Leaves blocks into Shredded Leaves Columns by putting them into a Processor (no crafting recipe is required). Shredded Leaves can also be used for crafting, mainly for Thatched Walls, Thatched Roofs, many types of Beds and several types of Carpets.
Parchwood Leaves can be used as a Fuel for the Forge, however 4 blocks of uncorrupted Leaves are required for each melting-/hardening-process and used up. Also each melting-/hardening process in the forge will take quite long when you use uncorrupted Leaves for a Fuel, since they are level 1 Fuel that burns the slowest.
Parchwood Leaves can be corrupted by throwing Corrupt Bombs at them. One Corrupt Bomb can corrupt up to 5x5x5 Leaves blocks, but usually only 5x5x3 Leaves. When picking up Corrupted Parchwood Leaves, they will turn into common Corrupted Leaves. These Leaves are common, but will not stack with Corrupted Ashenwood Leaves or Corrupted Elderwood Leaves.
Corrupted Leaves make for much faster burning Fuel of level 3, but they have to be picked up by using an equipped Diamond Mining Cell or Lumite Mining Cell, which will reduce the durability of these Power Cells quite a bit when pulling all kinds of Corrupted Blocks.
Corrupted Leaves of any kind cannot be processed into Shredded Leaves.
Corrupted Parchwood Leaves can only be turned into ordinary Parchwood Leaves if you have just corrupted Parchwood Leaves and have not picked them up. Then you can purify them with Purification Bombs or Healing Beacons.
One Healing Beacon can purify Corrupted Blocks and/or Corrupted Water in the range of two blocks to each side, but also downwards and upwards plus the one block that the Healing Beacon is placed on, and one block diagonally to all sides. Purification Bombs can purify up to 7x7x7 Corrupted Blocks at maximum, usually only 7x7x4 though.
If you collect Corrupted Parchwood Leaves, they will turn into common Corrupted Leaves in your quickbar and/or inventory/bag. You can still place them and purify them, but they will turn into Cragwood Leaves then.
Other uses for Parchwood Leaves
Since Parchwood Flowers do not exist, no tree Flowers will grow on Parchwood Leaves if you place them into the world.
You can still plant Queen Bees on Parchwood Leaves that will transform into Beeswax within ca. 3,5 hours real-life time when placed into suitable biomes (not too hot, not too cold, not on too high altitudes). The waiting time can be shortened for ca. 10-15 minutes if you fertilize the Queen Bees with Pigsy Droppings.
Other than that, Parchwood Leaves can also be put on display by placing them into the slots of display containers like Placemats, Stone Wall Shelves, Hidden Temple Altars, Galactic Grav-Chambers, Frozen Containers, Holiday Decorative Trees, Snow Buried Containers, Holiday Mantles, Wood Planters, Flower Pots or the like, where they will usually be reduced in size and cannot be rotated, corrupted nor burnt.