Selection criteria for class D timber
Class D- an experimental reserve of timber intended for storage for a period of5–20 years.
This is the initial research class of the system.DREVO Timber ReserveIt tests new species, wood preparation methods, storage types, and anaerobic conservation regimes.
Class D answers the main question: does it make sense to keep this wood longer?
Based on the observations, the material:
transferred to class C;
remains in an extended research program;
is extracted for practical use;
sent for processing;
excluded as unsuitable for long-term storage.
1. Class D assignment
Class D is created for:
testing new tree species;
study of different storage conditions;
comparison of wood with and without bark;
testing of various diving depths;
assessment of the impact of water, peat and bottom sediments;
determination of the rate of biological destruction;
studies of color and structure changes;
testing new labeling methods;
preparation of recommendations for classes C, B and A;
preventing the placement of large untested batches.
Class D is first and foremostscientific and technological testing ground, not a timber yard.
2. What breeds are accepted?
Class D may include virtually any legally obtained timber species, as long as the experiment has a clear purpose.
Main experimental groups
| Group | Examples | What is being checked? |
|---|---|---|
| Long-lasting deciduous trees | oak, chestnut, robinia, elm | Basic stability and property change |
| Medium-hardy deciduous trees | ash, maple, beech, birch | Possibility of long-term storage in water |
| Soft-leaved trees | willow, poplar, aspen, linden, alder | Rate of destruction and possible special applications |
| Conifers | pine, spruce, fir, larch, cedar pines | The influence of resin, water and temperature |
| Fruit | pear, apple, plum, cherry, apricot | Decorative and technological changes |
| Nut-bearing plants | nut, hazel, chestnut | Texture, color and stability |
| Prickly and drought-resistant | Gledichiya, Karagana, Hawthorn | Density and suitability for artistic processing |
| Large shrubs | red, lilac, birch, sea buckthorn | Experimental "marinating" |
| Invasive breeds | Robinia, Amorpha and other regional species | Possibility of beneficial use of removed biomass |
| Exotic breeds | only legally obtained samples | Comparative studies |
3. The main principle of selection
Wood is accepted into class D if it meets at least one criterion:
the breed has not been tested before;
new storage location;
new chemical composition of water;
a new way of preparing;
unusual wood shape;
new version of debarking;
new method of fixation;
new shelf life;
new type of bottom sediments;
unknown reaction to anaerobic environment;
the material has potential decorative or technical value.
An experiment without a clearly formulated question should not be launched.
4. Wood sources
| Source | Solution |
|---|---|
| Windfalls and windbreaks | High priority |
| Sanitary and emergency trees | Allowed |
| Clearing rivers and reservoirs | High priority |
| Restoration of floodplains and wetlands | Permitted after environmental assessment |
| Reconstruction of parks and roads | Allowed |
| Removal of invasive species | High experimental priority |
| Pruning large branches | Allowed |
| Horticultural and agroforestry farms | Allowed |
| Sawmill residues | Accepted as control samples |
| Illegal logging | Not permitted except for legally confiscated material |
| Cutting down healthy trees solely for the sake of experimentation | Not allowed |
5. Material dimensions
For class D there are no strict requirements for large diameter.
| Material type | Recommended sizes |
|---|---|
| Laboratory sample | From 20–50 cm in length |
| Control block | Approximately 5 x 5 x 30 cm or according to the program |
| Barrel disk | Thickness 5-15 cm |
| Branch or bush | Diameter from 3-5 cm |
| Small Ridge | Length 0.5–2 m |
| Working experimental barrel | Length 2–6 m |
| Large-sized trunk | Allowed, but preferably after small tests |
| Root part and burl | According to actual dimensions |
A unique solid barrel should not be placed in Class D immediately if the same conditions can be tested first on small samples.
6. Requirements for the party
Each experiment should include several comparable samples.
Minimal structure
at least 3 samples of one variant;
preferably 5-10 samples;
dry control;
water control;
early extraction sample;
sample for the average term;
sample for the full term;
backup sample.
Optimal comparative batch
| Variant | Quantity |
|---|---|
| With bark | 3–10 |
| Partially debarked | 3–10 |
| Fully debarked | 3–10 |
| With protected ends | 3–10 |
| With open ends | 3–10 |
| In the water | 3–10 |
| In the bottom silt | 3–10 |
| Dry control | 3–10 |
One sample does not allow one to reliably assess the properties of the entire rock.
7. Acceptable quality
Class D allows for a wider range of quality material than classes C, B and A.
Allowed:
knots;
curvature;
forks;
surface cracks;
local rot;
insect passages;
areas of the bark;
sapwood;
carbonization;
frost cracks;
mechanical damage;
root wood;
mouth guards and growths;
wood after floods;
wood that was previously in water.
Each defect must be measured and entered into the passport before storage.
8. What is not allowed
Even an experimental class should not accept hazardous material.
The following are not allowed:
radioactively contaminated wood;
wood with unknown industrial contamination;
material impregnated with petroleum products;
wood with hazardous chemical impregnations;
active quarantine pests without disinfection;
material that may contaminate other batches;
unknown origin;
illegally obtained timber;
wood that can degrade water quality;
samples without markings and research programs.
9. Ecological filter
Wood should not be taken from nature just because it is suitable for an experiment.
It remains in place if:
holds the shore;
creates shelter for fish;
serves as a spawning site;
used by birds;
contains a functioning hollow;
is a habitat for rare insects;
supports mushrooms and mosses;
retains water and organic matter;
performs an important function in a swamp or floodplain.
Only the ecologically acceptable part is taken for the experiment.
10. Types of experiments
D-Species
Testing a new breed.
D-Water
Comparison of different types of water:
river;
lake;
swamp;
mineralized;
slightly acidic;
neutral;
iron-containing.
D-Depth
Comparison of diving depths.
D-Sediment
Testing of various bottom environments:
sand;
open;
clay;
peat;
gravel;
mixed deposits.
D-Bark
Comparison of bark variants.
D-End Seal
End protection testing.
D-Season
Comparison of preparation times:
winter;
spring;
summer;
autumn.
D-Age
Comparison of young, mature and old-growth wood.
D-Shape
Testing of trunks, branches, roots, burls and shrubs.
D-Microbiology
Study of the influence of microorganisms.
D-Mineral
Study of the interaction of wood with iron and other natural minerals.
11. Experimental "marinating" of shrubs
Separate subcategory:
D-Shrub
Tested:
red;
hawthorn;
turn;
lilac;
hazel;
beresklet;
to look at;
they have become sea buckthorn;
honeysuckle;
large juniper;
boxwood - only legally obtained material;
Rhododendron and other species after toxicity testing.
The following are being investigated:
color change;
density;
hardness;
scent;
stability;
crack formation;
threadability;
the ability to manufacture small, precise products.
12. Selecting a storage location
Class D can be placed in:
small experimental tanks;
technical pools;
closed containers;
special cassettes in reservoirs;
research ponds;
controlled backwaters;
artificial marsh cells;
flooded quarries after assessment;
laboratory anaerobic chambers.
For the first tests, the following are preferred:controlled and reversible systems, from which samples can be easily extracted.
13. DREVO Test Cassette
It is advisable to place experimental samples in standard cassettes.
The cassette provides:
separation of breeds;
known position of samples;
protection against carry-over;
free contact with water;
contact with the selected sediment;
quick extraction;
installation of sensors;
saving identifiers.
Cassettes can have replaceable sections:
water;
open;
peat;
sand;
clay;
control air compartment.
14. Mandatory initial data
Before laying down the following are fixed:
| Parameter | Requirement |
|---|---|
| WOOD Timber ID | Necessarily |
| Batch ID | Necessarily |
| Type of wood | If possible, to the point of view |
| Origin | Exact territory and source |
| Date of preparation | Necessarily |
| Age | Known or estimated |
| Dimensions | Length, width, diameter |
| Weight | Original |
| Humidity | Original |
| Density | Desirable |
| Condition of the bark | Full description |
| Defects | Photos and measurements |
| Color | Standardized photography |
| Scent | Description if necessary |
| Chemical state | If there is a risk of contamination |
| Storage conditions | Water, depth, sediment |
| Extraction plan | Necessarily |
15. Minimum instrumental check
For class D the following are mandatory:
visual inspection;
measurement;
weighing;
photo recording;
humidity determination;
metal detector check;
description of damage;
origin analysis;
marking.
Additionally, the following are used:
ultrasound;
resistograph;
tomography;
microscopy;
chemical analysis;
dendrochronology;
genetic analysis;
testing the strength of control samples.
16. Storage periods
| Sub-step | Deadline | Task |
|---|---|---|
| D0 | 3–12 months | Early detection of destruction |
| D1 | 1–3 years | Primary compatibility |
| D2 | 3–5 years | Sustainability assessment |
| D3 | 5–10 years | Practical perspective |
| D4 | 10–20 years | Decision to transfer to class C |
The material does not have to be stored for the full 20 years. If unsuitability is detected earlier, the experiment is terminated.
17. Inspection schedule
| Period | Check |
|---|---|
| First month | Position and marking control |
| 3 months | Initial assessment |
| 6 months | Inspection of control samples |
| 12 months | Full annual report |
| 2–5 years | Annually |
| 5–10 years | Every 1-2 years |
| 10–20 years | Every 2-5 years |
For rapidly deteriorating rocks, monitoring is carried out more frequently.
18. What is measured after extraction
change in mass;
change in humidity;
density;
color;
scent;
hardness;
bending strength;
compressive strength;
impact strength;
softening depth;
rot;
fungal infection;
bacterial destruction;
shrinkage after drying;
tendency to crack;
sawdust quality;
planing quality;
suitability for grinding;
adhesive ability;
ability to accept finishing coatings;
decorative value.
19. Class D score
| Criterion | Maximum score |
|---|---|
| Scientific novelty | 20 |
| Potential practical value | 15 |
| Availability of material | 10 |
| Traceability of origin | 10 |
| Experimental safety | 15 |
| Possibility of comparison | 10 |
| Quality of the control group | 10 |
| Easy to monitor and retrieve | 10 |
| Total | 100 |
Decision to launch
| Points | Solution |
|---|---|
| 80–100 | Priority Experiment |
| 60–79 | Allowed |
| 40–59 | The program needs some improvement |
| Less than 40 | Do not run |
This rating shows the qualityexperiment, and not the wood itself.
20. Test results
Positive result
the material retains its structure;
no active rot;
physical properties are stable;
color or texture becomes more valuable;
the wood is dried successfully;
processing remains possible;
storage does not harm the reservoir;
marking and control work.
Neutral result
the wood is preserved, but its value does not increase;
Long-term storage has no clear advantage;
The material can be used after 5-20 years.
Negative result
rapid destruction;
loss of strength;
severe cracking after drying;
unpleasant persistent chemical changes;
water pollution;
inability to safely remove;
loss of markings;
economic senselessness.
21. Translation D → C
A party is transferred to class C if:
successfully completed at least one major control period;
retains beneficial properties;
does not create environmental risks;
has a clear future application;
storage technology is reproducible;
there is sufficient data;
a larger party can be formed;
The planned period is extended to 20–50 years.
22. Possible translation D → B
Direct translation is rarely possible if:
Already after the first few years, exceptional stability was revealed;
the breed has a high known longevity;
the specific trunks are of outstanding quality;
storage conditions are considered stable;
There are data from other long-term studies.
Usually the correct way is:
D → C → B → A
23. Exclusion from the program
The material is extracted if:
active destruction began;
there was a threat to other samples;
water quality has deteriorated;
the storage has become unstable;
identification lost;
the experiment cannot be continued;
no practical value;
the material is needed for more useful applications.
After exclusion, the timber can be sent to:
current processing;
biochar production;
composting - only safe wood;
energy use;
scientific samples;
artistic experiments;
return to the natural system, if permissible.
24. Class D subcategories
| Code | Purpose |
|---|---|
| D-Species | New breeds |
| D-Shrub | Shrubs |
| D-Water | Different types of water |
| D-Sediment | Various bottom sediments |
| D-Bark | Debarking options |
| D-Season | Harvesting season |
| D-Age | Age of the tree |
| D-Mineral | The influence of minerals |
| D-Microbiology | Microbiological processes |
| D-Shape | Branches, roots, burls and complex forms |
| D-Recovered | Wood extracted from rivers |
| D-Fire | Wood after a fire |
| D-Invasive | Removed invasive species |
| D-Technology | Marking, fastening and monitoring |
| D-Drying | Drying after extraction |
25. Digital passport class D
| Section | Data |
|---|---|
| Experiment ID | Experiment number |
| Timber ID | Sample ID |
| Batch ID | Batch number |
| Subcategory | Test type |
| Hypothesis | What is being checked? |
| Breed | Scientific and local name |
| Source | Origin of the material |
| Preparation | Bark, ends, processing |
| Initial state | Dimensions, weight, humidity |
| Storage | Type and coordinates |
| Wednesday | Water, silt, peat, sand or clay |
| Sensors | Established controls |
| Deadlines | Extraction plan |
| CONTROL | Comparative samples |
| Results | All dimensions |
| Solution | Continue, transfer or terminate |
| Next class | C, B or exception |
26. Difference between class D and class C
| Criterion | Class D | Class C |
|---|---|---|
| Shelf life | 5–20 years | 20–50 years |
| The main goal | Hypothesis testing | Practical reserve and extended testing |
| Breeds | Any promising | Already partially confirmed |
| Batch size | Small | Medium and large |
| Quality requirements | Wide | Higher |
| Control frequency | High | Moderate |
| Storage type | Preferably easily reversible | Long-term |
| Main result | Gaining knowledge | Obtaining material and knowledge |
| Translation | In class C | In class B |
27. Final selection criteria
Class D timber must:
have a legitimate origin;
be of scientific or practical interest;
be safe for storage;
to enter into a pre-designed experiment;
have control samples;
obtain full marking;
be available for intermediate extraction;
get checked regularly;
not be removed from an ecologically important place unless necessary;
produce a result that can be compared and repeated.
The main principle
Class D preserves not so much the wood itself as knowledge about its future.
This is the research basis of the entire system.DREVO Timber ReserveIt is the D class that allows for error-free testing on small batches before committing to large volumes of timber for 20, 50, 100, or 300 years.