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Zhongzhen Zhao Li Liang Eric Brand
Abstract: Agarwood refers to the very dense, dark, resin-enriched heartwood that is derived from various species of the genus Aquilaria (Thymelaceae). It is extremely valuable and is used as a source of fragrance, as medicine, and for carving.
Fragrant Harbor
Hong Kong has had a close relationship with agarwood throughout the city’s history.
As early as the Ming Dynasty, the area around Dongguan in Guangdong Province was known for its abundant agarwood. Sun Yat-sen’s home county, Zhongshan, was originally named “Xiangshan”(“fragrant mountain”) because of the agarwood that grew there. Xiangshan originally part of the Dongguan region; however, it was renamed Zhongshan County to honor Mr. Sun Yat-sen in 1925. In its early years, Hong Kong was the main port for overseas shipment of Dongguan’s fragrant materials, including agarwood. Over time, the name of the port became “Xiang Gang” which means “Fragrant Harbor” in Chinese, and which is pronounced “Heung Gong” in Cantonese. Thus, agarwood commerce is the source of Hong Kong’s name.
In 1997, to commemorate the return of Hong Kong to the motherland, 1997 agarwood trees were planted in Xianhu Botanical Garden in Shenzhen. On a hill in the botanical garden, the trees form the shape of a map of China, showing that Hong Kong and China, and that Hong Kong and traditional Chinese medicine, are closely related.
I am standing in Xianhu Botanical Garden in Shenzhen. The 1997 agarwood trees planted in the shape of the map of China are on the hillside behind me
Price Comparable to Gold
There is a unique street in Hong Kong called Ko Shing Street (also called “Herbal Medicine Street”), where many precious medicinal herbs are sold. When I was teaching, I often took students there to visit and study. Every time I went, I visited an old shop whose owner Mr. Chun-hung Lee would take out precious agarwood for our students to see. The elderly shopkeeper had a 700-gram piece of top-quality agarwood, valued at 8 million RMB (1.2 million USD).
Agarwood is so expensive mainly because it is so scarce. Not every agarwood tree produces agarwood; in fact, the formation of agarwood is a disease process.
The fragrance of agarwood comes from resin; healthy agarwood trees do not secrete resin. Only when the tree is injured—for example, when it is struck by lightning or attacked by insects—and the wound becomes infected by fungi do the trees secrete resin. In fact, “agarwood resin” in Chinese means “sick and healed wood”, Thus, in nature, agarwood can be found only by chance. Just as not every cow generates bezoar, and not every clamshell has pearls inside, only one out of a hundred agarwood trees has resin inside.
Kou Zongshi, author of Ben Cao Yan Yi in the Song Dynasty (960-1279), once worked in the Huimin Bureau of the Song Dynasty, where he was especially responsible for managing the medicinal material market, including identifying medicinal materials. In other words, he was roughly equivalent to the director of the current Food and Drug Administration. Kou Zongshi had extensive knowledge and rich experience in the identification of medicinal materials. In this book he records: “Some agarwood trees are so big that they require several people to hold a single one …But, among a hundred agarwood trees, it is hard to find one or two trees with agarwood resin.” The fact that this would be mentioned in such an old book shows how valuable and scarce this unusual material was, even at that time.
Agarwood Uses
One of the uses of agarwood is as a source of fragrance. In particular, it is an important raw material for incense products not only in China, but also in Japan, Korea, and Vietnam. China has a long history of using incense. Incense is burned to worship the Buddha and during meditation, as well as simply to scent the air. Yu Deling, a female official in the late Qing Dynasty, wrote in the “Royal Fragrance Ethereal Document (Yu Xiang Piao Miao Lu)” that the Empress Dowager Cixi loved to use agarwood. She reports, “There are many incense burners in the palace, and the smoke lingers.” It was, and is, believed that inhaling incense can purify the body and mind. This may be because certain components of agarwood resin can act on the central nervous system and calm the nerves.
The second use of agarwood is as medicine. This use of agarwood was first mentioned in the Ming Yi Bie Lu of the Southern and Northern Dynasties (420-589). This book lists agarwood as an “upper-rank” medicine. The Compendium of Materia Medica contains a dozen or so formulas containing agarwood, of which seven were newly added by Li Shizhen.
Agarwood is pungent, bitter, and slightly warm in nature. It has the effect of relieving pain by activating Qi, relieving vomiting, and relieving asthma. The classic proprietary Chinese medicines Zi Xue Dan, Si Mo Tang, and Su He Xiang Wan all contain agarwood. Modern research shows that agarwood has sedative, analgesic and antibacterial pharmacological activities.
The third use of agarwood is as a raw material for carving and handicrafts. I once saw a rhino horn-shaped cup made of agarwood in an exhibition, and it looked exactly like a real rhino horn cup. There are also many agarwood toys collected in the palace. Today, probably the most common form of carved agarwood is as beads which are strung together as bracelets. Such bracelets are used in meditation and/or collected. Over the years, I have collected agarwood bracelets of different origins and grades, and I keep them as precious treasures.
Agarwood is beautiful in its natural form. It has a smooth, even silky surface texture and subtle fragrance, with no need for carving. Thus, today, medicinal material stores and antique shops display agarwood in their front windows as a treasure.
Resource Distribution
Agarwood comes from several species of trees in the Thymelaeaceae family, mainly distributed in tropical and subtropical regions.
In China, domestic agarwood is derived from Aquilaria sinensis (Lour.) Gilg. This species is the only legal original plant source for its use as a medicine, according to the Chinese Pharmacopoeia (2020 edition). It mainly grows in Guangdong, Guangxi, Hainan and Fujian Provinces, and it has been planted on a large scale in Hainan.
The reproduction and growth of agarwood trees themselves is not difficult; the difficulty is in coaxing them to produce resin.
To increase the number of trees that produce agarwood resin, the ancestors invented artificial methods. In the period of the Republic of China (1912-1949), “Dongguan County Chronicle” recorded one artificial method that was used to encourage trees to produce resin. The trees were first cut to form an injured area to promote the formation of resin. This procedure was called “opening the resin door”, and it is still in use today.
Agarwood that fails to form resin cannot be used as medicine. It belongs to the category of “agarwood without resin”.
After “the resin door” is successfully opened, producing resin takes 10 to 20 years. Speeding up this process is impossible, as far as we know now.
Agarwood imported into China is derived from Aquilaria agallocha Roxb, another species of the same genus as the Chinese tree. The wood of this species is produced in Indonesia, Malaysia, Myanmar, Thailand, Vietnam, Laos, Cambodia and Bangladesh.
Nowadays, wild agarwood trees can hardly be found in China. In Vietnam, wild agarwood trees are also scarce, and the species is on the verge of extinction. At present, all wild species that produce agarwood are listed in, and protected by, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
Authenticity
There are four characteristics you can use to distinguish authentic from fake agarwood. One is its density. High-quality agarwood resin is very dense, with a large specific gravity. This means it sinks in water. As early as in the Compendium of Materia Medica, Li Shizhen mentioned: “The heartwood will sink when placed in water; hence it is called sinking in water (Chen Shui), also known as water sinking (Shui Chen).” Unfortunately, now there are cases of unscrupulous dealers artificially increasing the weight with foreign matter and compression, so “sinking in water” should not be the only way to assess the quality of a piece of supposed agarwood.
The second characteristic is its fragrance. True agarwood has a subtle, distinctive, ethereal fragrance that is very long-lasting. If a piece of supposed agarwood has a pungent smell, it has been tainted with additional spices or other chemicals. Texture is the third characteristic you can use to judge authenticity. High-quality agarwood should feel smooth, but not greasy. The ancients described this as no oil-releasing (Zou You) when touched. If there are oil marks left on your hands after touching it and the oil looks like a moisturizer, then the agarwood is probably fake.
Burning gives yet another clue. After agarwood is ignited, there should be a strong aroma, accompanied by the exudation of brown resin and emission of white smoke. High quality agarwood will slowly release different aromas at different temperatures and different stages of combustion. It’s just like a cup of tea, where different water temperatures and different brewing times give different tastes.
In addition to the above-mentioned empirical identification methods, test methods using analytical instruments and microscopes are also effective ways to evaluate the quality. I have conducted microscopic identification research on agarwood, and studied its microscopic characteristics such as its columnar calcium oxalate crystals. The “oil lines” visible in of agarwood are fibrous tracheids, vessels, resinous clumps, and parenchyma cells containing yellow-brown secretions. My research results, with photographs, have been included in The Pharmacopoeia of the People’s Republic of China – Color Atlas of Microscopic Identification of Traditional Chinese Medicine Powder.
In Quanzhou, Fujian Province, there are cultural relics salvaged in the 1970s from an ancient shipwreck of the Song Dynasty (700 years ago). The ancient ship was 24m long and 9m wide. It was very beautiful in shape and was considered to be a medium-sized ship at that time. In the hull were found porcelain, silk, spices and fragrant materials, such as agarwood, sandalwood, and frankincense. Today, this ancient ship is quietly displayed in a museum, silent witness to history and testament to the enduring allure of agarwood.
Author information:
Dr, Zhao Zhongzhen， Former deputy dean and professor of the School of Chinese Medicine of Hong Kong Baptist University, distinguished professor of Beijing University of Chinese Medicine, and founding director of the Compendium of Materia Medica Research Institute.
Dr. Li Liang Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Hong Kong.
Dr. Eric Brand Hong Kong Baptist University, 7 Baptist University Road, Kowloon Tong, Hong Kong.
沉香——亦香亦藥亦雕材
趙中振 梁鹂 Eric Brand
摘要：沉香木是瑞香科沉香屬多種樹木的富含樹脂的心材。可以熏香、可以入藥、可以雕刻，身價不菲。
運香之港
中國香港與沉香淵源頗深。
早在明代，東莞一帶盛產莞香等。孫中山的故鄉中山縣，原作香山縣，香山縣原隸屬東莞，南宋紹興二十二年（1152）分置，至1925年為紀念孫中山先生而改名中山縣。那裡栽培生長著沉香。香港充當了轉運東莞之香的主要港口。久而久之，運香之港就成了香港。
1997年，為紀念香港回歸祖國，深圳市仙湖植物園栽種了1997棵沉香樹，在園內的一座山上組成了中國地圖的形狀，展示了香港與祖國及香港與中藥的淵源。
我站在深圳仙湖植物園。1997年種植的中國地圖形狀的沉香樹就在我身後的山坡上
價若黃金
香港有條藥材街叫高昇街（別名藥材街），那裡銷售很多名貴藥材，我經常帶學生到那去見習考察。每次我都要去找一位老掌櫃，請他把一些珍貴沉香拿出來讓學生們開開眼。老掌櫃有一塊700克的極品沉香，被一位買主買走了，成交價800萬人民幣。
沉香如此昂貴，主要因為數量稀少，就算有沉香樹也不一定就能取到沉香。
健康的沉香樹木並不分泌起主要藥效的物質成分，只有當樹體受到傷害後，被雷劈或被蟲咬等情況發生後，傷口處被真菌感染了，植物出於自我防禦機制才會產生分泌物，才能形成沉香，通俗地說：“沉香”就是“生病的木頭”，可遇不可求。如同，不是每一頭牛都有牛黃，不是每個蚌殼裡面都有珍珠一樣。
宋代(960-1279)本草著作《本草衍義》的作者寇宗奭，曾任職宋代惠民局，專門負責管理藥材市場、鑒別藥材，大約相當於現在藥檢所的所長。寇宗奭兼通醫藥，藥材鑒別的經驗豐富。《本草衍義》書中就有這樣的記載：沉香木，大者合數人抱……有香者百無一二。
沉香用途
沉香的用途之一，是用來制香，它是高級香料製品的重要原料。香道中用沉香，不僅在我國如是，在日本、韓國、越南亦如是。沉香有悠久的用香歷史，在廟宇內燃香禮佛、參禪打坐時，都用的到香。清末女官裕德齡寫的《禦香縹緲錄》中記載了慈禧太后愛用沉香。宮裡有很多香爐，香煙繚繞，日日不絕，可以愉悅身心。
沉香的用途之二，是入藥。沉香入藥最早見於南北朝時期(420-589)的《名醫別錄》，書中將沉香列為上品。《本草綱目》裡一共收載了十幾首含沉香的複方，其中有七首方子是李時珍新增加的。
沉香味辛、苦，性微溫。有行氣止痛，溫中止嘔，納氣平喘的功效。經典的中成藥紫雪丹、四磨湯、蘇合香丸裡都含有沉香。且現代研究表明，沉香具有鎮靜、鎮痛和抗菌的藥理活性。
沉香的用途之三是做雕材、工藝品原料。我曾在一次展覽中見過沉香制的犀角形杯，看上去與真犀角杯別無二致。宮廷中收藏的沉香制把玩物件也非常多，用沉香製成的手串、把件是當下最火的木器文玩之一，也是很珍貴收藏品。這些年我收集了不同產地、不同等級的沉香手串，自己也把玩了好幾年。
沉香有自然的紋理、靜謐的幽香、天然的造形，不加雕飾已成大器。在很多藥材店鋪、古玩店鋪內，都會將沉香陳列於櫥窗前，作鎮店之寶。
資源分佈
沉香來源於瑞香科多種樹木，主要分佈在熱帶與亞熱帶地區。
國產沉香來源於瑞香科植物白木香Aquilaria sinensis (Lour.) Gilg含有樹脂的木材。白木香也是2020版《中國藥典》收載的中藥沉香的唯一法定原植物來源，主產於廣東﹑廣西﹑海南和福建等省區。
其實沉香樹的繁殖生長不太難，難在自然結香。
由於白木香自然繁殖率低，先人就發明瞭一種人工方法，定向培育沉香的技術。民國時期(1912-1949)《東莞縣誌》記載了用人工的方法讓樹木結香，先把樹木砍傷，促進沉香的形成，稱為“開香門”，這種方法一直沿用至今。
未能形成樹脂、沒能結香的沉香木，不能入藥，尚且屬於沒有香的沉香木。
結香的過程需要10到20年， 儘管在海南等地已大面積種植沉香，然而要等到結香、尚需時日。從事沉香行業急功近利是做不成的。
進口沉香是來源於瑞香科的另外一種植物Aquilaria agallocha Roxb.含有樹脂的木材，主產於印尼、馬來西亞、緬甸、泰國、越南、老撾、柬埔寨等地。
如今，野生沉香樹木，在我國已經基本看不到了。在越南，上等的沉香產量也很有限，瀕臨滅絕。目前所有產沉香的野生物種，均被列入了瀕危野生動植物種國際貿易公約。
真偽鑒別
沉香，顧名思義，入水而沉。早在《本草綱目》中李時珍就提到了：“木之心節置水則沉，故名沉水，亦曰水沉。”
但現在市場中出現人為增重、壓縮增重的情況，所以“入水而沉”不是唯一的標準了。
好的沉香，香氣若隱若現，而且十分持久。如遇到香味刺鼻者，往往是加入了香料或其他化學製品的。如果上手摸一摸，體會一下手感，摸著不膩手，即所謂“不走油”，便是優質沉香。如果摸完手上有油痕，好似潤膚霜，這便多為偽品。
沉香點燃後，應有強烈的香氣，並伴隨有褐色的樹脂滲出，煙色發白。
好的沉香在不同的溫度、燃燒的不同階段，會緩釋出不同的香氣。好似一杯茶，用不同的水溫、不同的時間泡，味道是不一樣的。
除了上述的經驗鑒別法，用儀器、顯微鑒別等試驗方法也是快速有效的。不但可用於鑒定沉香，也可用於鑒定其他貴重木材。
我曾對沉香進行過顯微鑒別研究，也對其中草酸鈣柱晶等重要顯微特徵進行過研究，沉香的“油線”是纖維管胞、導管、樹脂團塊和含有黃棕色分泌物的薄壁細胞。
這些研究結果，已被收入我主編的《中華人民共和國藥典——中藥粉末顯微鑒別彩色圖集》當中。
福建泉州有20世紀70年代打撈出水的出水文物——700年前的宋代古沉船。古船長24m，寬9m，造型非常優美，在當時屬於中等規模。在船體裡發現了瓷器、絲綢等貨物，其中還有沉香、檀香、降香、乳香、胡椒等香料。
如今那艘歷經滄桑的古船，靜靜的陳列在博物館內，作為歷史的見證者，默默地向來訪者訴說著海上絲綢之路、傳香萬裡的故事。
作者簡介：
趙中振 教授，香港浸信會大學中醫藥學院原副院長， 北京中醫藥大學特聘教授，本草綱目研究所創始所長。
梁鹂，博士，香港浸会大学，香港九龙塘浸会大学道7号[email protected]
Eric Brand，博士，香港浸会大学，香港九龙塘浸会大学道7号[email protected]
