Tree species identification service

Tree Species Identification Service – DNA Barcoding, Wood Anatomy and Forensic Timber Analysis for Bulgarian Forestry, Trade and Conservation

As an ISO/IEC 17025 accredited contract research laboratory, we offer specialised tree species identification services to Bulgarian and international clients in forestry management, timber trade, environmental conservation, furniture manufacturing, heritage conservation, and law enforcement. Accurate identification of tree species is essential for sustainable forest management, combating illegal logging, verifying timber origin for CITES compliance, assessing wood quality for construction and craftsmanship, and supporting ecological restoration projects. Our integrated approach combines classical wood anatomy (microscopic identification of cellular structures) with advanced molecular techniques – DNA barcoding, species‑specific PCR, and high‑throughput sequencing – to deliver reliable identification from a wide range of materials, including timber, leaves, seeds, bark, sawdust, wood chips, and charcoal. All methods are aligned with ISO 18087 (DNA barcoding for timber), IAWA (International Association of Wood Anatomists) guidelines, CITES (Convention on International Trade in Endangered Species) regulations, EU Timber Regulation (EUTR) No 995/2010, and BDS (Bulgarian Institute for Standardisation) requirements. Our reports are recognised by the Bulgarian Food Safety Agency (BFSA), the Ministry of Agriculture and Food (MAF) – particularly the Forestry Executive Agency, the Ministry of Environment and Water (MOEW), and the Executive Agency for Metrological and Technical Surveillance (IAМТН).

Tree Specimen and Wood Sample Types We Analyse

Our dendrology, wood anatomy, and molecular biology laboratories handle a broad variety of tree‑derived materials, from intact specimens to degraded forensic samples. Typical test articles include:

• Leaves and needles – fresh, dried, or herbarium‑preserved leaves, needles, and leaflets
• Seeds and fruits – cones, nuts, acorns, samaras, and seed fragments
• Wood samples – timber planks, logs, sawn boards, veneers, and craft wood
• Wood products – furniture components, flooring, panelling, doors, musical instruments, and handcrafted items
• Powdered and fragmented material – sawdust, wood chips, shavings, pellets, and briquettes
• Charcoal and archaeological wood – for heritage conservation and archaeological studies
• Bark, twigs, and roots – for species identification in forensic and ecological contexts
• Herbarium specimens and museum samples – for verification and curation

Wood Anatomy – Microscopic Identification of Cellular Structure

• Macroscopic examination – wood colour, grain pattern, and porosity – We examine the wood surface (end‑grain, radial, and tangential sections) to assess colour, texture, grain pattern, and ring structure. This provides an initial indication of the genus or species (e.g., oak, ash, pine, walnut).
• Preparation of thin sections – hand sections or microtome cutting – We cut thin slices (10‑20 µm) from the wood sample using a microtome or a sharp razor blade, producing transverse, radial, and tangential sections. The sections are stained with safranin or other dyes to highlight diagnostic anatomical features.
• Optical microscopy – cellular examination at 50‑400× magnification – We examine the prepared sections under a compound microscope to observe diagnostic features: vessel size and arrangement, parenchyma distribution, fibre type and wall thickness, and the presence of tyloses, crystals, and resin canals. We follow the IAWA List of Microscopic Features for Hardwood Identification and IAWA Softwood Identification Atlas.
• Comparison with reference collections – We compare the observed anatomy with our curated reference collection of over 1 000 wood samples from Bulgarian and European trees (including regional species such as beech, oak, hornbeam, fir, spruce, pine, larch, birch, and maple), as well as with international databases and regional herbaria.
• Identification of CITES‑listed species – using wood anatomy and molecular confirmation – For protected species (e.g., Swietenia macrophylla, Dalbergia spp., Guibourtia spp., Pterocarpus spp.), we combine wood anatomy with molecular barcoding to provide a robust, court‑admissible identification.

DNA Barcoding – Molecular Identification for Difficult and Degraded Samples

• DNA extraction – from wood, leaves, cambium, and processed materials – We use specialised extraction kits (e.g., DNeasy Plant Mini Kit, CTAB‑based protocols) to isolate high‑quality DNA from a wide variety of starting materials, including dried leaves, cambium, sawdust, and even processed wood. For degraded or old samples (e.g., antique furniture or charcoal), we use kits designed for forensic DNA recovery.
• PCR amplification – using standard plant barcoding markers – We amplify a combination of plant barcoding loci to achieve species‑level resolution: rbcL (ribulose‑1,5‑bisphosphate carboxylase gene), matK (maturase K gene), ITS (Internal Transcribed Spacer region), and trnH‑psbA (intergenic spacer). For wood and degraded samples, we use shortened mini‑barcodes (150‑300 bp).
• Sanger sequencing and sequence quality control – The PCR products are sequenced using Sanger technology (bidirectional), and the resulting sequences are carefully checked for base‑calling accuracy (Phred score ≥ 30) and manually edited to remove ambiguous bases.
• Database comparison – using BOLD, GenBank, and in‑house reference libraries – We compare the obtained sequence against public databases (GenBank, BOLD) and our curated in‑house reference library of over 1 500 Bulgarian and European tree species. Species identification is based on the percentage similarity and the phylogenetic placement (using BLASTn and phylogenetic analysis). A match with ≥ 99 % similarity to a reference sequence of the same species is considered high‑confidence; 98‑99 % indicates a closely related species; lower matches may indicate a need for further analysis (e.g., multi‑locus sequencing).
• Multi‑locus sequencing – for resolving closely related species – For species that are not resolved by the standard barcodes (e.g., many Quercus and Ulmus species), we sequence additional loci (e.g., LEAFY, G3PDH, or microsatellites) and construct a concatenated phylogenetic tree (using Maximum Likelihood or Bayesian methods) to identify the species.
• Species‑specific PCR and real‑time qPCR – rapid screening of target species – For high‑throughput screening or for detecting specific CITES‑listed species (e.g., Dalbergia nigra, Swietenia macrophylla), we develop and validate species‑specific qPCR assays (TaqMan or SYBR Green) with high sensitivity and specificity.

Forensic Wood Identification – For Customs, Enforcement and Court Cases

• Illegal logging and CITES enforcement – identification of protected timber – We identify timber species in confiscated shipments, customs seizures, and construction materials to verify compliance with CITES and the EU Timber Regulation (EUTR). Our reports are admissible in Bulgarian and European courts and support the Forestry Executive Agency and National Customs Agency.
• Identification of species in processed timber products – furniture, flooring and construction materials – We identify the species used in finished products (e.g., parquet, veneer, musical instruments, turned items) even when the wood is stained, painted, or glued. This is essential for verifying the origin and legality of the timber, as well as for heritage conservation and antique restoration.
• Wood ageing and comparison – for archaeological and art historical contexts – We combine wood anatomy and DNA analysis with radiocarbon dating (if required) to determine the species and age of archaeological wood, structural timber, and wooden artefacts, supporting Bulgarian museums and heritage conservation bodies.
• Detection of wood fraud – mislabelled timber and false declarations – We verify the identity of timber declared as a certain species (e.g., “mahogany” or “walnut”) and detect fraud by species substitution (e.g., Entandrophragma spp. for Swietenia spp.).

Species Identification for Specific Applications – Forestry, Ecology and Industry

• Forest inventory and biodiversity monitoring – identification of standing trees – We identify tree species from leaf, seed, and bark samples collected during forest inventories, supporting sustainable forest management plans and biodiversity assessments for the Bulgarian Forestry Executive Agency and private forest owners.
• Timber quality and wood property assessment – species‑specific grading – We identify the species to predict wood properties (density, hardness, decay resistance, workability) for construction, furniture making, and specialised industries (e.g., musical instruments, shipbuilding).
• Invasive species detection and monitoring – rapid identification of non‑native trees – We identify invasive tree species (e.g., Robinia pseudoacacia, Ailanthus altissima) to support the Ministry of Environment and Water (MOEW) in monitoring and controlling invasive species.
• Seed and fruit identification – for seed banks and tree nurseries – We identify tree seeds and fruits (cones, nuts, acorns) to ensure that seed banks and nurseries maintain correct stocks and to prevent the introduction of non‑native genotypes.
• Phytosanitary screening – detection of pest‑related tree damage – We identify the tree species from samples showing disease or pest symptoms, which helps in diagnosing the cause and in implementing appropriate quarantine measures for BFSA and the National Plant Protection Organization.

Quality Control, Reference Collections and Data Integrity

To ensure the reliability and reproducibility of our tree species identifications, we maintain rigorous internal quality controls:

• Reference wood collection – we have an extensive reference collection of wood samples from Bulgarian and European tree species (over 1 000 species) and a growing collection of tropical timber. Each specimen is vouchered with herbarium material for morphological and molecular verification.
• Reference DNA library – we maintain a comprehensive DNA barcode library for Bulgarian and European trees, which is regularly updated and cross‑referenced with public databases (GenBank, BOLD).
• Positive and negative controls in molecular runs – each PCR plate includes positive controls (DNA from a known reference species) and negative controls (water) to monitor for contamination and amplification efficiency.
• Proficiency testing and inter‑laboratory comparison – we participate in external proficiency testing schemes (e.g., FAPAS, and inter‑laboratory comparisons organised by European reference laboratories) to verify the accuracy of our molecular and anatomical identifications.
• Blind testing and internal audits – we perform regular internal blind tests, where samples of known identity are submitted to our team to verify the consistency of identification protocols.

Reporting – Comprehensive Documentation and Data Delivery

Our final tree species identification report provides a complete, transparent, and traceable record of the identification process. The report includes:

• Sample information – unique sample ID, material type, collection location, date, and collector details
• Method summary – a detailed description of the anatomical (IAWA features) and/or molecular methods (markers, primers, PCR conditions) used
• Results – for wood anatomy: a description of the diagnostic features observed, the identification key used, and the final identification (genus and species); for DNA barcoding: the raw sequence(s), the best‑matching reference sequences with accession numbers, the percentage similarity, and the phylogenetic tree (if multi‑locus).
• Interpretation and confidence – a clear statement of the identification (e.g., Quercus robur – English oak) and a confidence level (e.g., “high confidence”, “moderate confidence”, or “tentative”), with comments on any limitations.
• Images and supplementary data – high‑resolution photomicrographs (anatomical sections), photographs of the specimen, gel images, and sequence chromatograms are included as supplementary material.
• Compliance statement – a statement that the identification follows the relevant standard (ISO, IAWA, CITES, EUTR) and is suitable for the intended use (e.g., forestry, trade, forensic).

Report Acceptance & Compliance with Bulgarian and European Regulatory Frameworks

All tree species identification tests are performed under our ISO/IEC 17025 accreditation and, where applicable, in compliance with Good Laboratory Practice (GLP) principles and the EU Timber Regulation (EUTR). Our reports are prepared in accordance with the requirements of the Bulgarian Ministry of Agriculture and Food (MAF) – particularly the Forestry Executive Agency, the Ministry of Environment and Water (MOEW), the Bulgarian Customs Agency, and the Bulgarian Food Safety Agency (BFSA) for phytosanitary and forest health purposes. The reports are also accepted by international bodies such as CITES and INTERPOL for enforcement and trade compliance. Bilingual (Bulgarian/English) versions are available to facilitate submissions to national and European authorities and to support scientific publications and international collaboration.