The Biology of Liftwood
by Marcus L. Rowland

Despite the fact that space travel and flight are almost wholly dependent on liftwood, little is known about the plant's biology. It should be emphasized that much of what follows is based on examination of a very small number of specimens; liftwood species only develop their antigravity properties in the soil of the remote high kraags of Mars, and expeditions to these regions are invariably attacked by thieves or the barbaric High Martians. There has been little opportunity to study these curious plants in their native habitat. The physics and chemistry of the liftwood effect remain an enigma.
Liftwood
Liftwood is the generic name for a group of similar plant species (Lignivolucer var.) found exclusively on Mars. No close correspondence to any Terran plant family exists. The seeds show unique dispersal mechanisms.
Main Species
Three species have been studied - they are the most widely cultivated types. They are named for the areas where they were first seen by Terran scientists.

    L. aeria is the broad-leafed species first reported by Edison on his return from Mars. It is the most common form and is now known to be widely distributed throughout the Martian heights. The physical properties of L. aeria are used as the standard by which other liftwoods are judged. Mature plants produce wood that is usable for approximately 10 years.
    L. edensis was first reported in the Eden hills and has a broad north-south distribution in mountain ranges from Cydonia to Noarchis. The plant is smaller than L. aeria and tends to produce less usable wood for a given volume of timber. However, it is believed to tolerate poorer soil conditions than L. aeria. This is probably the reason why its lifting power and service life are half that of L. aeria.
    L. arabia is distributed sparsely through the Arabia, Meroe, and Tempe mountains. It is a smaller tree, but the trunks are generally knot-free and give a good yield of usable wood - up to a third more than L. aeria for a given volume of logs. Lifting power is roughly 1.5 times that of L. aeria, and the service life is longer; it is usable for approximately 12 years after harvesting.

Pollination
All liftwood plants produce pollen and are prepared to receive it throughout the Martian year. The plants are apparently capable of self-pollination, but this has not been confirmed experimentally. The pollen is extremely fine-grained, on a par with that of the finest grasses. It does not appear to have any antigravity effect, but its size and the fierce mountain winds ensure that grains stay airborne for many months. Scientists have collected samples at all altitudes and over all areas of Mars, including the poles and deserts.
Biological Role of Antigravity
At first sight, there seems to be no obvious natural need for the antigravity properties of liftwood; the plant dies if uprooted, so it is apparently unable to take advantage of this capability. The importance of this characteristic only becomes apparent if the habitat of the plant is considered. Liftwood plants are dependent on the soil of the high kraags; they can be cultivated elsewhere but seldom reach maturity, rarely bear seed, and do not show any antigravity properties. Other plants which only grow in the same areas and seem to require the same soil do not develop the liftwood capability.

Thus, it seems clear that the soil fulfills some nutritive need; the antigravity effect is secondary to this need.

As yet it has proven impossible to make a careful survey of many liftwood groves. On the evidence available, it would appear that similar liftwood plants are found in widely separated areas of Mars, but the other species associated with liftwood groves are far more varied, often unique to a single mountain. Two conclusions are possible: Either the liftwood species have been widely distributed by the High Martians, or their spread is aided by their remarkable properties. Although the High Martians undoubtedly cultivate and spread these plants, discoveries of isolated plants and untended groves suggest that they can spread unaided. Wild liftwood is generally 10 to 20 percent weaker (in terms of the antigravity effect) than cultivated plants. Wild liftwood also gives lower yields of usable straightgrained wood. A rumor persists that wild liftwood is better, but this is untrue.

On Earth most seeds are distributed by animals or the wind. On Mars there are significant barriers to animal distribution, primarily huge expanses of and land where animal life is scarce. Liftwood plants have an additional handicap - their need for special soils. To take full advantage of suitable habitats, all known liftwood species are able to propagate by the use of runners (like banyan or strawberry plants). However, dispersal beyond these areas requires a mobile seed; in view of the vast distances involved, a flying seed is preferable. The three species studied all produce seeds which show the liftwood effect. Escaped slaves report that High Martian liftwood farmers remove most of the seeds as they form; thus, this may make the trees retain more of the liftwood chemical and is possibly one of the reasons why cultivated liftwood is more powerful than wild plants.

L. edensis shows a good example of this form of seed dispersal. The pea-sized seed trails thin root-like tendrils which do not have any gravity-negative property. The seed is initially able to lift its own weight plus the weight of the tendrils. Seeds float slowly upward from the plant, dispersing widely on the mountain updraft. After a few hours, the seed loses a little lift and is gravitationally neutral, staying at a constant altitude for weeks or months. Not surprisingly, this altitude happens to be ideal for the species. Drifting flight continues until the tendrils touch any solid object. Within a few moments of contact, the seed loses some buoyancy and sinks until approximately half the length of the tendrils rests on the ground. With some of the load removed, the seed remains airborne and continues to drift, dragging the tendrils behind it. When the tendrils encounter a patch of suitable nutritious soil, thin root hairs dig in to anchor the seed and slowly pull it into the ground.

One drawback of the method used by L. edensis is that the low-altitude flight is triggered by accidental contact with the ground. Given a strong updraft, it is possible for such seeds to encounter a mountain and fly over it without ever making this initial contact.

This problem is avoided by the acorn-sized seeds of L. aeria. L. aeria secretes the lift chemical in the seed and in leaf-like vanes attached to it. The vanes are arranged to make the seed spin if they catch the wind. The seed trails a single tendril with a bulbous tip. Like L. edensis, L. aeria is initially gravity-neutral. However, after a few days, the vanes dry, and their point of attachment becomes extremely brittle. If the seed then encounters turbulent winds, such as the updrafts near a mountain, the vanes snap off, and some lift is lost. The seed descends until the tendril touches the ground and commences low-altitude trailing flight, in the manner of L. edensis. If suitable soil is encountered, four barbed hooks spring out, anchoring the seed while the root tips grow. Extension of the hooks takes approximately three seconds and appears to use a mechanism similar to the collapse of leaves on the Terran mimosa plant.

A simpler method is used by L. arabia, the smallest of the common liftwood species. Thousands of tiny seeds are produced, each topped by an oval disk - a 'float' of gravity-negative material. This seed is stable in calm conditions but tilts and loses much of its lift when it encounters turbulence. It then descends randomly and starts to grow regardless of the type of soil. Most of the seeds die, but a small portion fall onto suitable soil.
Other Species

At least two other liftwood species may exist, but they are only known from second-hand accounts, wood, and fruit. As yet, no Terran scientist has seen the actual plants, and scientific names have not been assigned.

    Shiuuskup is a rare Martian fruit that resembles a sweet blue apricot with a spicy aftertaste. It is much prized by Martian gourmets and can be fermented to make an extremely potent liqueur. If the oval seeds are carefully removed, they float upward. It is assumed that these seeds are normally dispersed by animals, possibly the flying skrill or one of its smaller relatives. The seeds retain the antigravity ability, which is used if animals are not available. There is no obvious mechanism for efficient airborne distribution, unlike the other large seeds studied. Experiments show that the seeds lose their antigravity effect after passing through the gut, which would support this theory. Presumably uneaten fruit rots to release the seeds, which drift off in any wind. Martian sources claim that the plant is a bush, not a tree, and does not produce usable liftwood, but this has not been verified. It apparently has a limited range in the Noachis heights.
    Seerdiik is an extremely rare, dense liftwood with straight grain and very powerful antigravity effects. A piece of seerdiik will lift approximately twice the load of a similar volume of L. aeria. It is claimed to retain its lift for 20 to 30 Martian years, far longer than other species. The largest piece examined by Terran scientists is the hull of a model ether-flyer, given to a British merchant by the Amwaak of Parhoon shortly before he was assassinated. The uncut wood was approximately a foot long by four inches square. The grain patterns suggest that it may have been cut from the main trunk, which would appear to be no more than six to eight inches wide. The source of seerdiik remains unknown. Unreliable reports say that it is a dwarf hybrid species cultivated by members of a civilized High Martian tribe, but this seems extremely unlikely.

The Otterwood Expedition, 1887-8
In 1887 naturalists working at the Royal Botanical Gardens decided to mount an expedition to obtain samples of liftwood plants, the soil they grow in, and associated plant and animal species. The expedition was led by Dr. John Otterwood, a botanist who had previously been involved in expeditions to the Congo and Upper Amazon. For logistical reasons, the explorers decided to visit the Astusapes Highlands.

Unfortunately, it took some time to arrange the hire of a steam launch and other equipment, and the departure from Parhoon has delayed until February of 1888, a few days before the Kraag Barrovaar incident.

For some time, there was no news of the expedition, and it was feared that the explorers had been caught up in the fighting that led to the Oenotrian War. These fears were justified; an Oenotrian Bloodninnerkite encountered the launch on its return journey and attacked it.

The scientists (armed only with a Nordenfelt machinegun and small arms) retaliated by running the launch into the kite's sails and setting them on fire, then picked off the kite's crew as they tried to extinguish the blaze. The kite ultimately crashed, with no survivors. The launch was badly damaged in the fight and made a forced landing in the Meroe Badlands. The scientists escaped across country and eventually reached Parhoon but were forced to abandon the soil samples and most of their equipment. Otterwood's leg was broken in the crash and became gangrenous during the return journey; he died less than a week after the expedition returned.

Seed specimens and drawings returned by members of the expedition were one of the principal sources for this article.
Game Use - Space 1889
Adventurers are more likely to be interested in the commercial and military uses of liftwood than in its botany or ecology. However, this research can lead to some, interesting plot ideas.

    The adventurers trade for liftwood. During the return journey, they realize that the liftwood they are carrying is L. edensis, not L. aeria, and has less than a quarter of the value they expected - probably not enough to pay their expenses and debts.
    Seerdiik contains an unusually stable and concentrated form of the liftwood chemical. Given a large sample, it might be possible to make a detailed analysis and discover its secrets. The only accessible sample is a model ether flyer, the pride and joy of a rich Parhooni merchant who has no intention of selling it.
    Where does seerdiik grow, and who (or what) grows it? Could there be civilized High Martians?
    Shiuuskup plants are cultivated as food, not for their antigravity capability. Can the plant be grown in a more civilized setting? If so, will it have the taste that Martian gourmets expect from this delicacy?
    Somewhere in the Meroe Badlands is the wreck of the Otterwood Expedition launch, containing several hundred pounds of liftwood grove soil, a variety of plants and seeds, and scientific instruments. Have the Oenotrians found it? If not, is there anything worth salvaging? Did anyone ever salvage the Bloodrunner kite?

Game Use - Sky Galleons of Mars
L. arabia gives more lift than normal liftwood - usually 150 tons per hull size number but up to a maximum of 240 tons per hull size number. It costs £8000 per hull size in Martian yards (but is usually unavailable; roll 1D6 plus hull size to determine the number of months needed to obtain the supply necessary for a given vessel). British yards can never get large quantities. At best, they can supply enough for one hull size for £12,000, but it will take 2D6 months to obtain the wood. To calculate the lift of a hull built from L. arabia, use Lv=l 5OHs/T, where Lv is lift value, Hs is hull size, and T is tons.

L. edensis gives less lift than normal liftwood - usually 50 tons per hull size number but up to a maximum of 80 tons per hull size number. It costs £3000 per hull size in Martian yards, £5000 per hull size in British yards. However, the disadvantages of this wood mean that no yard routinely stocks it. It must be ordered (delay 1D6 months) or supplied by the purchaserof the hull. In practice, it is mainly used for small craft, conveyers, and other applications where strong lift capability isn't needed. To calculate the lift of a hull built from L. edensis, use Lv=50HS/T.

For a steel hull (British yards), add £2000 per hull size to the cost of the wood.

If these variant woods are used, the exact type of hull should be noted on the ship record form (e.g., L. arabia wooden hull, steel-clad L. edensis, etc. For game purposes, species of liftwood with different lift values cause trim instabilities and cannot be mixed in the construction of a hull.

Seerdiik is not available for ship construction.
The Otterwood Incident
The material presented here will permit interested players to recreate the Otterwood party's encounter with the hostile kite.

Map: Use the Kraag Barrovaar map from Sky Galleons of Mars. Each brown line is a terrain boundary. The highest point on the map is at high altitude. Ignore all ground installations apart from the trees on the smaller peak.

Ships: The British have an aerial steam launch:
Move: 5; Hull Size: 1; Armor: 0; Bridge: C, H, T; Passengers: 4; Wpn: Nordenfelt gun bearing forward, port, starboard; Cost: £4840; Weight: 50 tons; Max. Height: VH.

All passengers and crew have modern rifles. The passengers of the launch count as Green crew when using weapons; one of the passengers must man the gun. For ship plans and other information, see Space: 1889.

The Martians have a standard Bloodrunner kite with a Trained crew.

Setup: The British launch begins landed on the smaller peak, height Medium. The Martin kite begins on the edge beyond the other peak, height High.

Special Rules: Neither craft is a military vessel, but the kite captain is sure that he can take on one puny launch. He will attack until his ship is damaged or crew is killed, then try to withdraw. The British launch must defend itself, and the captain won't willingly retreat from natives without serious damage. For the purposes of this combat, a boarding party may deliberately start fires with damage value 1.

Victory: The British win if the kite retreats off the map or is destroyed or disabled, and they are then able to leave the map. The Martians win if the launch is captured, destroyed, or disabled.

Posted Monday, 04-May-2009 19:52:42 EDT