Chapter XIII.
On the usefulness and diversity of trees; on the method of grafting and healing them; finally, on the properties of tree sap: with a moral explanation for each point.
53. But why should I dwell only on human life, when all kinds of trees are useful, some created for fruit, others for utility? For even those without abundant fruit have a precious use. The cedar is suitable for hanging roofs, because this type of wood is tall and spacious, but not burdensome to the walls. The cypress is also suitable for ceilings and gables. Hence, the Church says in the Canticles: 'The beams of our houses are made of cedar, our ceilings of cypress' (Song of Songs 1:16), explaining that the decorations of its structure are in these, as if the beams sustain the crown of the Church with their own strength and adorn its peak. The laurel and the palm are the symbols of victory. The heads of the victors are crowned with laurel, and the hand of the conqueror is adorned with a palm. Hence the Church says: I said, I will go up to the palm tree, I will take hold of its branches (Song of Songs, 7:8). Seeing the excellence of the Word and hoping that she can ascend to His height and the summit of knowledge, she says: I will go up to the palm tree, so that she may leave behind all lower things and strive for higher things, for the reward of Christ, so that she may enjoy and taste the sweet fruits of His love. For the fruit of virtue is sweet. The people also declare mystically with crowns the victorious shady tree, and the flexible willow useful for binding vines, what else do they declare except that the bonds of Christ are good, which do not harm, the bonds of grace, the bonds of charity, so that everyone may boast in their own bonds, just as Paul also boasted, saying: Paul, a prisoner of Jesus Christ (Philem. I, 1)? Bound by these bonds, he said: Who shall separate us from the love of Christ? (Rom. VIII, 35)? The chains of abstinence, the chains of charity. Bound by these chains, David also says: In the willows, in the midst thereof, we hung up our harps (Ps. CXXXVI, 2). Likewise, the boxwood tree, useful for carving the tips of musical instruments, shapes the skill of a young hand with its light material. Hence the Scripture says: Write in boxwood (Esa., XXX, 8). At the same time, may the very material that is always green and never sheds its leaves remind you to never be exposed by the dissimulation of your hope, but may it always bring forth hope of salvation to you through faith.
Why should I enumerate the great variety of trees, the diverse and beautiful adornment in each one, the expansive beech trees, the tall firs, the abundant pines, the shady oaks, the two-colored poplars, the wooded and evergreen chestnut trees, which, when cut down, are accustomed to sprout as if a forest from themselves; just as in the trees themselves, either a mature or a young age is found; for the younger ones have thinner branches, while the older ones have stronger and knotty limbs: the former have smooth and spread-out leaves, the latter have more condensed and rough leaves. There are also trees that, even with an old and dead root, do not know how to regenerate themselves if they are cut down. Others, in which either youth flourishes or nature is more fruitful, benefit from being cut down, so that they are renewed through the succession of their offspring.
There is also, something which you may marvel at, distinction of sex even in fruits, and distinction of sex in trees. For you may see a palm which bears dates, mostly bending its branches and submitting them, and assuming the appearance of desire and embrace to that tree, which boys of the country call a male palm. Therefore, that palm is of linen, and confesses its sex by the appearance of submission. Hence, the tillers of the place throw upon the branches of it the seeds of date-palms, or shoots of male trees, with which seeds the female tree, as it were with some representation of performance, is impregnated, and the desired cohabitation is represented. By this skill, when again given, it is raised up and lifts its branches and raises its hair again to its old condition. The same opinion is held about the fig tree. And therefore many people are said to graft a wild fig tree onto a domestic and fruitful fig tree, because the fruits of that fertile and domestic fig tree are reported to fall quickly either by an attempted breeze or by heat to the ground. Hence those who are knowledgeable about this, bind the branches of the wild tree to that fruitful tree in order to heal its weakness, so that it may be able to save its own fruits, and soon if they are in danger of being destroyed, the remedies will be about to fall. In this way, we are reminded not to give up on those who have separated from our faith and community, as if they were a puzzle of nature. The more serious the proponent of the error, the more vehemently they can become a defender of the faith. And if someone converts from heresy, they can confirm the side they have turned to, especially if they have something directly related to nature. Their viewpoint can be vivid if supported by the attention of sobriety and the observance of chastity. Therefore, immerse yourself deeply in your study of him, so that you may strengthen your virtue through the fruitful likeness of that fig tree, from its presence and connection to that rustic tree. For in this way, your intention will not be dissolved, and the fruits of diligence and grace will be preserved.
But there are many things that teach that natural hardness can be tempered by the study of diligence, as the example of rural cultivation brings! For often, pomegranate trees quickly bloom, but they cannot bear fruit unless they are cultivated with proper remedies by experts: often the juice fades away internally, and its strong appearance is displayed beautifully. This can rightfully be compared to the Church, as you have in the Song of Songs directed to the Church: Your cheeks are like the skin of a pomegranate (Song of Songs, 4:3). And below: If the vine flourished, the pomegranates also flourished (Song of Songs, VII, 12). For the Church presents the good splendor of faith and confession, with the beauty of many martyrs' blood, and what is more, endowed with the blood of Christ; at the same time, preserving many fruits within itself by the use of this fruit under one protection, and encompassing many matters of virtue. For the wise spirit conceals affairs. Farmers are also said to heal the almond tree with this kind of medicine, so that its bitter fruits become sweet, and also to burn its root and insert a branch of that same tree, which the Greeks call a 'pine', but we call it a fir tree; by doing this, the bitterness of the sap is removed. Therefore, if agriculture can transform the qualities of plants, can the pursuit of knowledge and the attention to discipline not mitigate any ailments of the passions? Therefore, no one positioned in the slippery slope of youth or intemperance should despair of their transformation. Wood is usually transformed into better uses, can't hearts of humans be changed?
We have learned that not only among different kinds of trees are there diversities of fruits, but often within the same species of trees the fruits themselves are in conflict with one another. For there is one species of male fruits, another of female fruits, as we have stated above concerning dates. But who can comprehend the variety, the species, and the charm of apples, and the individual usefulness of each fruit, and the properties of the juices that seem suitable to each thing? For example, how bitter apples can heal sickly organs of human bodies, and how they can reduce internal inflammation and roughness, and how, conversely, the roughness of certain juices can be tempered by the sweetness of apples. Finally, that more ancient medicine, which used to heal with herbs and juices; and there is no stronger health than the one that is restored by wholesome foods. Therefore, according to nature, we are taught that food alone is medicine for us. Certainly, external wounds are closed with herbs, and internal ones are healed with herbs. And that's why it is the task of doctors to know the powers of herbs. From here, the practice of healing has become ingrained.