At first I roughly marked the outlines of the tree trunk but started to add characteristic structures of the bark very soon. Typically one can see the many layers of the bark pieces on pine trunks at the two sides or outline of the trunk. (see video below).
Towards the viewer the bark appears as a more or less regular pattern of stretched,vertical irregular forms with more or less deep,dark wells in between.
I did not try to copy what I saw exactly one to one, that could take a very long time to do and often such drawings look stiff later. Instead I started with characteristic forms at the base of the trunk and then worked upwards by adding structures from the sides working inwards. My guideline were the dark wells, that I drew between the bark pieces. Over time the structures got more and more dense and the impression of pine tree bark developed without painstaking efforts to copy each and every detail.
To represent the surface of the bark pieces I rolled a charcoal pieces slightly with my index fingers over the white paper (see video below).
Thus I could create an irregular, light pattern that resembles the appearance of the bark. Up to then I had not paid attention to the shadows on the tree trunk.
On the right : the Initial outline drawing
Left: Initial state, adding dark lines and the deep wells right: The dense pattern of bark pieces and dark wells in between.
At the end I tried to add some shadows by moving a bigger piece of charcoal over those parts that I saw in shadows. As the light moved fast in the evening I had to study the form of the shadows at some other trees because the shadows on my study subject had gone already.
Left: Finished study Right: detail of the trunk base
Drawing a group of pine trees
This exercise begins in the same way as the previous ones: With light touch the bigger forms and Proportions of tree tops,the position and length of the trunks and the surroundings are explored. At that stage corrections can be made easily and indeed I wiped out some initial lines once or twice in this case.
Then more details and structures are added until the final stage of the drawings is reached.
The form of the charcoal pieces is very well suited to represent the structure of the typical needle bundles in pine tree tops. By varying the pressure on the charcoal one can create parts in shadow or parts in light. Again the eraser helped to put in light strokes into areas already covered with charcoal pigments. Short dark strokes or dots were added to enhance the impression of the short needle bundles.
I also tried to imitate the quirky growth of the pine branches and twigs. Typical for pines are also those short, dark dead branches below the tree top.
Left: after the basic proportions are laid down further detail was added.The eraser was used to rework some dark areas with structures. That process was repeated several times until the desired look was achieved.
Right: After the pine tree were mostly finished the undergrowth was added in broad strokes with a bigger charcoal piece and various pressure. The tree top of small tree in sunlight at the edge of the forest was left in almost untouched white.
Left: detail of the tree tops, on top of the medium and light layers there are dark marks, some of them lightened up with the eraser, additional short marks and dots were added to resemble the needle bundles.
Right: Detail of the undergrowth ,the eraser was formed to a round tool to create the structures that look similar to the foliage of shrubs and beech trees.
The eraser was used to create the structure of deciduous foliage of shrubs and beech trees as well as for the grass in the foreground. Near the bench one can see how light grass was added by drawing with the eraser into dark areas.