Gerald Koch is the curator of the scientific wood collection of th ü Nen Institute in Hamburg, Germany. There, scientists have access to tens of thousands of recorded wood samples.

Written by Peter Yeung

On a cold winter day in Hamburg, Germany, Gerald Koch slowly moved away from the black microscope, raised his head, adjusted his rimless glasses, and then pointed to a piece of suspected illegal wood thinner than his hair on the display.

"Based on these two things, I can immediately judge that it is from South America," he said, pointing to a pair of huge white cells on the charcoal canvas. "This is due to our years of experience."

The tunang Institute is located in the suburbs of Hamburg, Germany. It is composed of a group of dull concrete buildings built in the 1960s. It is a world leading center for combating international crime. The quiet corridor may be a little inconsistent with this identity. There are 1500 tree species in the laboratory on the second floor, which is the most important wood Certification Center in the world.

"A lot of illegally cut timber is difficult to track, and the information declared by the customs is often wrong," said Koch, head of the Institute's timber producing area center. "Our job is to uncover the truth."

According to the data of Interpol, the illegal timber industry is the third largest criminal industry in the world after drugs and counterfeit goods, with an annual output value of 152billion US dollars. With the prosperity of global timber trade - the export price of forest products quadrupled from 1980 to 2020 - People's awareness of illegal trade is also increasing. WWF estimates that 16 to 19 per cent of EU timber imports are of illicit origin.

With financial support from the German government, the Hamburg Institute provides government agencies, timber traders and consumers with scientific and authoritative certification on the origin of timber products.

A team of 15, including four forensic scientists, checks a series of strange wood products every day - from children's toys, window frames, clothes hangers to umbrella handles - to determine where they are made and whether they are made of endangered or protected trees. If any samples are found to be in violation of the European timber regulations (which have banned illegal timber imports since 2013) or the Washington Convention on international trade in endangered species (a multilateral treaty for the protection of plants and wildlife), the team will notify the German authorities.

On the door of Koch's lab was a sign that half jokingly said "wood detective".

The wood samples of the tunang Research Institute represent the most important international trade wood varieties, with about 400 species.

Moldy wood archives

The wood Library of tunang Research Institute is called the wood library. It has 41000 samples from 11300 different tree species. It is one of the largest certified wood specimen collections in the world. It is precisely because the collection is very rich in samples that the research team can compare the new samples with a large number of collections, and then determine the genera and species of almost all trade timber - legal or illegal.

In a moldy room, thousands of samples were arranged on the shelves in different colors. The other room contains rare tree species, such as the 300 year old trunk of Siberian larch; A Mexican bowling ball made of guaiac wood, which is one of the most dense and hard wood known, and weighs as much as coal; A tool used to fix the stones of the pyramids during the reign of Thutmosis III around 1400 BC.

In 2021, tunang Research Institute released about 1000 depth reports on wood and 10000 analysis reports on individual samples. "There has never been a sample that we couldn't confirm," Koch said Up to 25% of the samples proved to be incorrectly declared.

During the identification process, researchers will cut a piece of wood from each sample, boil it in water for 30 minutes to remove bubbles, and then plane it into slices for microscopic observation. Then these samples were analyzed under the microscope and compared with tens of thousands of samples in the digital database.

Authentication requests come from all over the world, but more than three-quarters of them are European companies doing due diligence. They hope to ensure the legitimacy of product materials.

"Are these decorative panels made of durable Balau wood or poor quality wood substitutes? Are the origin of these mahogany logs properly declared? Are the import documents correct and authentic? These are just some questions we must answer," Koch said.

Faith Doherty, leader of the forest movement of the environmental investigation agency, an international non-profit organization that collects on-site evidence of illegal logging, said that one document alone was not convincing. "It is now very clear that signing a document is not enough to guarantee verifiability," she said. "We need to go to the field to see what happened and analyze the products being produced."

Since the establishment of the center of competence on origin of timber in 2013, orders for wood anatomical analysis have more than tripled. However, the proportion of false declarations has decreased - which is seen as a sign of improvement.

John Hermanson, a research scientist at the school of environmental and Forest Sciences at the University of Washington, believes that the work of the Institute is more important than ever before. "They play an important role in this global issue," he said. "They actively participated in the global community, and built a bridge between science and practice, exposing these cases for the authorities."

Hermanson is developing a handheld device called xylotron for the U.S. Forest Service, which can use the Bureau's own wood warehouse for scanning and rapid identification. He said: "it is difficult to obtain high-quality samples. It costs too much, so a wood library like Germany is very useful."

Prepare microscopic sections for wood anatomical identification. The thickness of each thin piece of wood is 0.02mm, which is not as thick as a hair.

The fluorescence test of dissolved wood should be irradiated with long wave ultraviolet ray.

Still have blind spots

Wood detectives have limited abilities. Although they can identify the genus of a sample, it is much more difficult to determine the exact species or geographical origin. The same tree species may grow in many countries or even continents; Timber may be harvested, processed and manufactured into products for sale in several regions. The fibers of paper products are impregnated, so it is more difficult to analyze, and the problems are more difficult.

"A notebook may be made of wood from three continents and eight countries - the hardcover cover cover, front page and inside page may be different," Hermanson said.

However, the Institute studies the sustainable use of natural resources in agriculture, forestry and fisheries. It is multidisciplinary, so Koch's team of wood anatomists can obtain professional knowledge from forest genetics, trade and economics experts in other departments. Forgery experts can sniff out forged customs documents; Geneticists can find clues to the geographical origin of a piece of wood.

However, blind spots still exist - for example, genetics cannot verify whether wood is wild or grown in plantations, which is crucial to determining whether wood is illegal. The Institute is developing the use of stable isotope analysis, a process that measures the proportion of specific chemical elements (such as nitrogen) that are heavier or lighter in the sample and can help determine the geographical origin of wood.

"Wood anatomy, which has been used for a century, must be combined with other techniques." Peter Gasson, chief wood anatomist of Kew Royal Botanical Gardens, said. "The combination of two or three technologies will lead to a more accurate answer." He participated in the worldforest ID project, a new project run by the alliance of organizations to improve wood certification.

At the same time, emerging technologies can greatly improve the efficiency and capacity of the Institute. In a three-year collaboration with the research institute Fraunhofer Institute, researchers used microscope specimens to train artificial intelligence software to identify wood. Andrea olbrich, the project leader, said: "it can complete the work that our team usually needs a month to complete in one night."

However, at present, with the rapid development of logging in Asia, Africa, Latin America and Siberia, the old-fashioned detection method of Gerald Koch and his detective partners is still the main method to identify illegal timber. Their huge archives need to be expanded. A study published in January this year estimated that there were about 73000 tree species in the world, 14% higher than the currently known figure.

"We are still a long way from collecting all the tree species," Koch said. "We must continue to work on this basis to improve our knowledge. Although our methods are improving every day, the criminals we fight against are also improving."