This post hasn't had a response, but it has merit, because I've found someone else who thinks that the trees ought to be a little more dense too! I suspect there are others . . . . . This fix is a biggish subject, and whether easy or hard will depend upon one's xml and 7Days modding experience.
Sorry - I'm not aware of any existing replacements for the actual trees themselves, though I expect they may be in a few mods out there: however - I do use Doughphungus's very comprehensive "Punishing Weather" series of climate altering mods which are ready-to-use, and quite modifiable to suit your taste. He also has a "daylight length" mod included in his A2- Main download.
Regarding tree density - yes it can be done 'moderately' easily, depending upon your own level of expertise with xml and the 7D2D filesystem. I reckon the 'best' way is to create your own 'Mods' folder, then a 'Config' folder inside it, and then a single 'biomes.xml' file inside that. You can also edit the original biomes.xml too, but the rewards by learning how to make your own mod yourself are much greater. Part of my little experiment (prompted by your post) is below.
Each of the original game's biomes xml file has sections for each biome, (i.e. desert, snow, pine forest, burnt forest, wasteland) and inside each biome are several subbiomes, plus one for the applicable weather. Each subbiome is different, but only identified their numerical probability. In the Pine Forest there are: <subbiome prob="0.27">, <subbiome prob="0.31">, <subbiome prob="0.392">, <subbiome prob="0.412"> and <subbiome prob="0.442">.
The one I changed was at the bottom of the pine forest section - the Block Layers: Pine Forest -> "Decorations Main:" . This contains the 'general' vegetation decoration for the whole of the PF biome.
As this was an experiment, and using the Advanced RWG - I created the small (3072x3072) map as a single biome - the Pine Forest, to keep the build-time down. First I commented out the trees and bushes from each of the PF's 'probability' subbiomes in the main game files. This might not have been neccessary, but I wanted to see the impact of my mod changes without seeing the default as well. Next I created a biomes.xml for the \Mod\Red22(my mods name)\Configs\ and changed the trees in the 'Decorations Main' section as below:
foliage and planted foods changes to the P.Forest Primary Biome using parts from or in addition to n2n1's Classic Hard Core mod.
<append xpath="/worldgeneration/biomes/biome[@name='pine_forest']">
<decorations>
<decoration type="block" blockname="plantedMushroom3Harvest" prob="0.003" rotatemax="7"/>
<decoration type="block" blockname="plantedCorn3Harvest" prob="0.003" rotatemax="7" />
<decoration type="block" blockname="plantedPotato3Harvest" prob="0.0035" rotatemax="7" />
<decoration type="block" blockname="plantedBlueberry3Harvest" prob=".003" rotatemax="7" />
<decoration type="block" blockname="plantedGoldenrod3Harvest" prob="0.007" rotatemax="7" />
The next three are courtesy of n2n1's "Classic Hard Core" overhaul mod, and make for a most believable "abandoned" look.
<decoration type="block" blockname="fern01" prob="0.5" rotatemax="7" /><!-- Orig .2 -->
<decoration type="block" blockname="nettle" prob="0.5" rotatemax="7" />
<decoration type="block" blockname="burdock01" prob="0.5" rotatemax="7" />
<decoration type="block" blockname="deadTree01Fall" prob="0.0004" rotatemax="3"/>
<decoration type="block" blockname="Trunk01" prob="0.0005" rotatemax="3"/>
<decoration type="block" blockname="Trunk02" prob="0.0005" rotatemax="3"/>
<decoration type="block" blockname="treeBush01" prob="0.5" rotatemax="7"/><!-- Orig .005 -->
<decoration type="block" blockname="treeBush02" prob="0.5" rotatemax="7"/>
<decoration type="block" blockname="treeBush03" prob="0.5" rotatemax="7"/>
<decoration type="block" blockname="treeAzalea" prob="0.01" rotatemax="7"/>
<decoration type="block" blockname="treeDeadPineLeaf" prob="0.005" rotatemax="7"/>
<decoration type="block" blockname="treeJuniper4m" prob="0.04" rotatemax="7"/> <!--All trees are .0001 by default -->
<decoration type="block" blockname="treeMountainPine12m" prob="0.005" rotatemax="7"/>
<decoration type="block" blockname="treeMountainPine19m" prob="0.005" rotatemax="7"/>
<decoration type="block" blockname="treeMountainPine27m" prob="0.005" rotatemax="7"/>
<decoration type="block" blockname="treeMountainPine31m" prob="0.01" rotatemax="7"/>
<decoration type="block" blockname="treeMountainPineDry21m" prob="0.001" rotatemax="7"/>
<decoration type="block" blockname="treeOakMed01" prob="0.010" rotatemax="7"/>
<decoration type="block" blockname="treeOakMed02" prob="0.010" rotatemax="7"/>
<decoration type="block" blockname="treeOakSml01" prob="0.010" rotatemax="7"/>
<decoration type="block" blockname="treeOakLrg01" prob="0.020" rotatemax="7"/>
<decoration type="block" blockname="treeFirLrg01" prob="0.0003" rotatemax="7"/>
<decoration type="block" blockname="treeMountainPine48m" prob="0.0005" rotatemax="7"/>
<decoration type="block" blockname="treeStump" prob=".0004" rotatemax="7"/>
<decoration type="block" blockname="treeTallGrassDiagonal" prob=".5"/>
<decoration type="block" blockname="treeShortGrass" prob=".5"/>
<decoration type="block" blockname="treeBrownGrassDiagonal" prob="0.5"/>
</decorations>
<subbiome prob="0.402"> <!-- Ore Sub Biome: oilDeposit *** -->
<layers>
<layer depth="1" blockname="terrForestGround"/>
<layer depth="3" blockname="terrDirt"/>
<layer depth="1" blockname="terrStone">
<resource blockname="terrGravel" prob="0.7830" rwgGenerationType="all"/>
</layer>
<layer depth="*" blockname="terrStone"> <resource blockname="terrOreOilDeposit" prob="0.6500" rwgGenerationType="all"/>
<resource blockname="terrGravel" prob="0.7830" rwgGenerationType="all"/>
</layer>
<layer depth="3" blockname="terrBedrock"/>
</layers>
<decorations>
<decoration type="prefab" name="deco_shale_vein" checkresource="-7" onslopes="true" prob=".00657" rotatemax="3"/>
<decoration type="block" blockname="rockResource" prob=".00033" rotatemax="3"/>
<decoration type="block" blockname="rockResource02" prob=".00033" rotatemax="3"/>
<decoration type="block" blockname="cntForestRandomLootHelper" prob="0.00025"/>
<decoration type="prefab" name="rock_form02" prob=".001" rotatemax="7"/>
<decoration type="prefab" name="rock_form01" prob=".001" rotatemax="7"/>
<decoration type="block" blockname="rock01" prob=".001"/>
<decoration type="block" blockname="rock02" prob=".001"/>
<decoration type="block" blockname="rock04" prob=".001"/>
<decoration type="block" blockname="cntBirdnest" prob="0.0005"/>
</decorations>
</subbiome>
</append>
The above, then, was the biomes.xml for my mod. The next addition was to do something about the 'darkness" issue: There is a lot written by both Donovan and Doughphungus - both are geniuses in this field. I am not anywhere close to genius - in any field, I just like 'playing'/ In this case all I did was take Donovan's suggestion for the fogPower level in the worldglobal.xml:
<configs>
<set xpath="/worldglobal/environment/property[@name='fogPower']/@value">1,0.40</set>
</configs>
Default is 1,1 - day,night.
I hope that helps, and gives you some ideas. It has worked in this experiment, and I shall expand upon it in future games. Sorry to be so long-winded!!
